[RMXP] Getting an error in Law's CMS

I managed to fix all the other errors I've gotten with this script, but this one has me stumped.
It works fine, but when I try to go to the Item menu I get this error:

Spoiler for error:

My CMS script is:

Spoiler for script:

#==============================================================================
# ** Scene_Menu
#------------------------------------------------------------------------------
#  This class performs menu screen processing.
#==============================================================================

class Scene_Menu
  #--------------------------------------------------------------------------
  # * Object Initialization
  #     menu_index : command cursor's initial position
  #--------------------------------------------------------------------------
  def initialize(menu_index = 0)
    @menu_index = menu_index
  end
  #--------------------------------------------------------------------------
  # * Main Processing
  #--------------------------------------------------------------------------
  def main
    # Make command window
    s1 = $data_system.words.item
    s2 = $data_system.words.skill
    s3 = $data_system.words.equip
    s4 = "Status"
    s5 = "Save"
    s6 = "End Game"
    @command_window = Window_Command.new(160, [s1, s2, s3, s4, s5, s6])
    @command_window.index = @menu_index
    # If number of party members is 0
    if $game_party.actors.size == 0
      # Disable items, skills, equipment, and status
      @command_window.disable_item(0)
      @command_window.disable_item(1)
      @command_window.disable_item(2)
      @command_window.disable_item(3)
    end
    # If save is forbidden
    if $game_system.save_disabled
      # Disable save
      @command_window.disable_item(4)
    end
    # Make play time window
    @playtime_window = Window_PlayTime.new
    @playtime_window.x = 0
    @playtime_window.y = 224
    # Make steps window
    @steps_window = Window_Steps.new
    @steps_window.x = 0
    @steps_window.y = 320
    # Make gold window
    @gold_window = Window_Gold.new
    @gold_window.x = 0
    @gold_window.y = 416
    # Make status window
    @status_window = Window_MenuStatus.new
    @status_window.x = 160
    @status_window.y = 0
    # Execute transition
    Graphics.transition
    # Main loop
    loop do
      # Update game screen
      Graphics.update
      # Update input information
      Input.update
      # Frame update
      update
      # Abort loop if screen is changed
      if $scene != self
        break
      end
    end
    # Prepare for transition
    Graphics.freeze
    # Dispose of windows
    @command_window.dispose
    @playtime_window.dispose
    @steps_window.dispose
    @gold_window.dispose
    @status_window.dispose
  end
  #--------------------------------------------------------------------------
  # * Frame Update
  #--------------------------------------------------------------------------
  def update
    # Update windows
    @command_window.update
    @playtime_window.update
    @steps_window.update
    @gold_window.update
    @status_window.update
    # If command window is active: call update_command
    if @command_window.active
      update_command
      return
    end
    # If status window is active: call update_status
    if @status_window.active
      update_status
      return
    end
  end
  #--------------------------------------------------------------------------
  # * Frame Update (when command window is active)
  #--------------------------------------------------------------------------
  def update_command
    # If B button was pressed
    if Input.trigger?(Input::B)
      # Play cancel SE
      $game_system.se_play($data_system.cancel_se)
      # Switch to map screen
      $scene = Scene_Map.new
      return
    end
    # If C button was pressed
    if Input.trigger?(Input::C)
      # If command other than save or end game, and party members = 0
      if $game_party.actors.size == 0 and @command_window.index < 4
        # Play buzzer SE
        $game_system.se_play($data_system.buzzer_se)
        return
      end
      # Branch by command window cursor position
      case @command_window.index
      when 0  # item
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to item screen
        $scene = Scene_Item.new
      when 1  # skill
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Make status window active
        @command_window.active = false
        @status_window.active = true
        @status_window.index = 0
      when 2  # equipment
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Make status window active
        @command_window.active = false
        @status_window.active = true
        @status_window.index = 0
      when 3  # status
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Make status window active
        @command_window.active = false
        @status_window.active = true
        @status_window.index = 0
      when 4  # save
        # If saving is forbidden
        if $game_system.save_disabled
          # Play buzzer SE
          $game_system.se_play($data_system.buzzer_se)
          return
        end
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to save screen
        $scene = Scene_Save.new
      when 5  # end game
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to end game screen
        $scene = Scene_End.new
      end
      return
    end
  end
  #--------------------------------------------------------------------------
  # * Frame Update (when status window is active)
  #--------------------------------------------------------------------------
  def update_status
    # If B button was pressed
    if Input.trigger?(Input::B)
      # Play cancel SE
      $game_system.se_play($data_system.cancel_se)
      # Make command window active
      @command_window.active = true
      @status_window.active = false
      @status_window.index = -1
      return
    end
    # If C button was pressed
    if Input.trigger?(Input::C)
      # Branch by command window cursor position
      case @command_window.index
      when 1  # skill
        # If this actor's action limit is 2 or more
        if $game_party.actors[@status_window.index].restriction >= 2
          # Play buzzer SE
          $game_system.se_play($data_system.buzzer_se)
          return
        end
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to skill screen
        $scene = Scene_Skill.new(@status_window.index)
      when 2  # equipment
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to equipment screen
        $scene = Scene_Equip.new(@status_window.index)
      when 3  # status
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to status screen
        $scene = Scene_Status.new(@status_window.index)
      end
      return
    end
  end
end

And my Scene_Item is:

Spoiler for:

#------------------------------------------------------------------------------
#==============================================================================
#==============================================================================
#====================*Law's Custom Menu Screen*================================
#=========================Author: The Law G14==================================
#============================Version 1.0=======================================
#==============================================================================
#------------------------------------------------------------------------------
#==============================================================================
# ** Game_Map
#------------------------------------------------------------------------------
#  This class handles the map. It includes scrolling and passable determining
#  functions. Refer to "$game_map" for the instance of this class.
#==============================================================================

class Game_Map
  #--------------------------------------------------------------------------
  # * Public Instance Variables
  #--------------------------------------------------------------------------
  attr_accessor :tileset_name             # tileset file name
  attr_accessor :autotile_names           # autotile file name
  attr_accessor :panorama_name            # panorama file name
  attr_accessor :panorama_hue             # panorama hue
  attr_accessor :fog_name                 # fog file name
  attr_accessor :fog_hue                  # fog hue
  attr_accessor :fog_opacity              # fog opacity level
  attr_accessor :fog_blend_type           # fog blending method
  attr_accessor :fog_zoom                 # fog zoom rate
  attr_accessor :fog_sx                   # fog sx
  attr_accessor :fog_sy                   # fog sy
  attr_accessor :battleback_name          # battleback file name
  attr_accessor :display_x                # display x-coordinate * 128
  attr_accessor :display_y                # display y-coordinate * 128
  attr_accessor :need_refresh             # refresh request flag
  attr_reader   :passages                 # passage table
  attr_reader   :priorities               # prioroty table
  attr_reader   :terrain_tags             # terrain tag table
  attr_reader   :events                   # events
  attr_reader   :fog_ox                   # fog x-coordinate starting point
  attr_reader   :fog_oy                   # fog y-coordinate starting point
  attr_reader   :fog_tone                 # fog color tone
  attr_reader   :name
  #--------------------------------------------------------------------------
  # * Object Initialization
  #--------------------------------------------------------------------------
  def initialize
    @map_id = 0
    @display_x = 0
    @display_y = 0
  end
  #--------------------------------------------------------------------------
  # * Setup
  #     map_id : map ID
  #--------------------------------------------------------------------------
  def setup(map_id)
    # Put map ID in @map_id memory
    @map_id = map_id
    # Load map from file and set @map
    @map = load_data(sprintf("Data/Map%03d.rxdata", @map_id))
    # set tile set information in opening instance variables
    tileset = $data_tilesets[@map.tileset_id]
    @tileset_name = tileset.tileset_name
    @autotile_names = tileset.autotile_names
    @panorama_name = tileset.panorama_name
    @panorama_hue = tileset.panorama_hue
    @fog_name = tileset.fog_name
    @fog_hue = tileset.fog_hue
    @fog_opacity = tileset.fog_opacity
    @fog_blend_type = tileset.fog_blend_type
    @fog_zoom = tileset.fog_zoom
    @fog_sx = tileset.fog_sx
    @fog_sy = tileset.fog_sy
    @battleback_name = tileset.battleback_name
    @passages = tileset.passages
    @priorities = tileset.priorities
    @terrain_tags = tileset.terrain_tags
    # Initialize displayed coordinates
    @display_x = 0
    @display_y = 0
    # Clear refresh request flag
    @need_refresh = false
    # Set map event data
    @events = {}
    for i in @map.events.keys
      @events = Game_Event.new(@map_id, @map.events)
    end
    # Set common event data
    @common_events = {}
    for i in 1...$data_common_events.size
      @common_events = Game_CommonEvent.new(i)
    end
    # Initialize all fog information
    @fog_ox = 0
    @fog_oy = 0
    @fog_tone = Tone.new(0, 0, 0, 0)
    @fog_tone_target = Tone.new(0, 0, 0, 0)
    @fog_tone_duration = 0
    @fog_opacity_duration = 0
    @fog_opacity_target = 0
    # Initialize scroll information
    @scroll_direction = 2
    @scroll_rest = 0
    @scroll_speed = 4
    @name = load_data("Data/MapInfos.rxdata")[@map_id].name
  end
end

#==============================================================================
# ** Window_Location
#-----------------------------------------------------------------------------
# A window that shows your current Location.
#==============================================================================

class Window_Location < Window_Base
  #-----------------------------------------------------------------------------
  # * Object Initialization
  #-----------------------------------------------------------------------------
  def initialize
    super(0, 0, 160, 96)
    self.contents = Bitmap.new(width - 32, height - 32)
    refresh
  end
  #-----------------------------------------------------------------------------
  # * Refresh
  #-----------------------------------------------------------------------------
  def refresh
    self.contents.clear
    self.contents.font.color = system_color
    self.contents.draw_text(4, 0, 120, 32, "Location")
    self.contents.font.color = normal_color
    self.contents.draw_text(4, 32, 120, 32, $game_map.name, 2)
  end
end

#==============================================================================
# ** Window_MenuStatus
#------------------------------------------------------------------------------
#  This window displays party member status on the menu screen.
#==============================================================================

class Window_MenuStatus < Window_Selectable
  #--------------------------------------------------------------------------
  # * Object Initialization
  #--------------------------------------------------------------------------
  def initialize
    super(0, 0, 480, 480)
    self.contents = Bitmap.new(width - 32, height - 32)
    refresh
    self.active = false
    self.index = -1
  end
  #--------------------------------------------------------------------------
  # * Draw Face Graphic
  #     actor : actor
  #     x : draw spot x-coordinate
  #     y : draw spot y-coordinate
  #--------------------------------------------------------------------------
  def draw_actor_face_graphic(actor, x, y)
     bitmap = RPG::Cache.picture(actor.id.to_s)
     self.contents.blt(x, y, bitmap, Rect.new(0, 0, bitmap.width, bitmap.height))
   end
  #--------------------------------------------------------------------------
  # * Refresh
  #--------------------------------------------------------------------------
  def refresh
    self.contents.clear
    @item_max = $game_party.actors.size
    for i in 0...$game_party.actors.size
      x = 64
      y = i * 116
      actor = $game_party.actors
      draw_actor_face_graphic(actor, x - 64, y)
      draw_actor_name(actor, x + 93, y)
      draw_actor_class(actor, x + 135, y + 32)
      draw_actor_level(actor, x + 40, y + 32)
      draw_actor_state(actor, x + 270, y)
      draw_actor_exp(actor, x + 40, y + 64)
      draw_actor_hp(actor, x + 236, y + 32)
      draw_actor_sp(actor, x + 236, y + 64)
    end
  end
  #--------------------------------------------------------------------------
  # * Cursor Rectangle Update
  #--------------------------------------------------------------------------
  def update_cursor_rect
    if @index < 0
      self.cursor_rect.empty
    else
      self.cursor_rect.set(0, @index * 116, self.width - 32, 96)
    end
  end
end

#==============================================================================
# ** Scene_Menu
#------------------------------------------------------------------------------
#  This class performs menu screen processing.
#==============================================================================

class Scene_Menu
  #--------------------------------------------------------------------------
  # * Object Initialization
  #     menu_index : command cursor's initial position
  #--------------------------------------------------------------------------
  def initialize(menu_index = 0)
    @menu_index = menu_index
  end
  #--------------------------------------------------------------------------
  # * Main Processing
  #--------------------------------------------------------------------------
  def main
    # Make command window
    s1 = $data_system.words.item
    s2 = $data_system.words.skill
    s3 = $data_system.words.equip
    s4 = "Status"
    s5 = "Save"
    s6 = "End Game"
    @command_window = Window_Command_New.new(160, [s1, s2, s3, s4, s5, s6])
    @command_window.index = @menu_index
    @command_window.height = 225
    @command_window.x = 480
    # If number of party members is 0
    if $game_party.actors.size == 0
      # Disable items, skills, equipment, and status
      @command_window.disable_item(0)
      @command_window.disable_item(1)
      @command_window.disable_item(2)
      @command_window.disable_item(3)
    end
    # If save is forbidden
    if $game_system.save_disabled
      # Disable save
      @command_window.disable_item(4)
    end
    # Make play time window
    @playtime_window = Window_PlayTime.new
    @playtime_window.x = 480
    @playtime_window.y = 224
    # Make location window
    @location_window = Window_Location.new
    @location_window.x = 480
    @location_window.y = 320
    # Make gold window
    @gold_window = Window_Gold.new
    @gold_window.x = 480
    @gold_window.y = 416
    # Make status window
    @status_window = Window_MenuStatus.new
    @status_window.x = 0
    @status_window.y = 0
    # Execute transition
    Graphics.transition
    # Main loop
    loop do
      # Update game screen
      Graphics.update
      # Update input information
      Input.update
      # Frame update
      update
      # Abort loop if screen is changed
      if $scene != self
        break
      end
    end
    # Prepare for transition
    Graphics.freeze
    # Dispose of windows
    @command_window.dispose
    @playtime_window.dispose
    @location_window.dispose
    @gold_window.dispose
    @status_window.dispose
  end
  #--------------------------------------------------------------------------
  # * Frame Update
  #--------------------------------------------------------------------------
  def update
    # Update windows
    @command_window.update
    @playtime_window.update
    @location_window.update
    @gold_window.update
    @status_window.update
    # If command window is active: call update_command
    if @command_window.active
      update_command
      return
    end
    # If status window is active: call update_status
    if @status_window.active
      update_status
      return
    end
  end
  #--------------------------------------------------------------------------
  # * Frame Update (when command window is active)
  #--------------------------------------------------------------------------
  def update_command
    # If B button was pressed
    if Input.trigger?(Input::B)
      # Play cancel SE
      $game_system.se_play($data_system.cancel_se)
      # Switch to map screen
      $scene = Scene_Map.new
      return
    end
    # If C button was pressed
    if Input.trigger?(Input::C)
      # If command other than save or end game, and party members = 0
      if $game_party.actors.size == 0 and @command_window.index < 4
        # Play buzzer SE
        $game_system.se_play($data_system.buzzer_se)
        return
      end
      # Branch by command window cursor position
      case @command_window.index
      when 0  # item
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to item screen
        $scene = Scene_Item.new
      when 1  # skill
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Make status window active
        @command_window.active = false
        @status_window.active = true
        @status_window.index = 0
      when 2  # equipment
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Make status window active
        @command_window.active = false
        @status_window.active = true
        @status_window.index = 0
      when 3  # status
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Make status window active
        @command_window.active = false
        @status_window.active = true
        @status_window.index = 0
      when 4  # save
        # If saving is forbidden
        if $game_system.save_disabled
          # Play buzzer SE
          $game_system.se_play($data_system.buzzer_se)
          return
        end
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to save screen
        $scene = Scene_Save.new
      when 5  # end game
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to end game screen
        $scene = Scene_End.new
      end
      return
    end
  end
  #--------------------------------------------------------------------------
  # * Frame Update (when status window is active)
  #--------------------------------------------------------------------------
  def update_status
    # If B button was pressed
    if Input.trigger?(Input::B)
      # Play cancel SE
      $game_system.se_play($data_system.cancel_se)
      # Make command window active
      @command_window.active = true
      @status_window.active = false
      @status_window.index = -1
      return
    end
    # If C button was pressed
    if Input.trigger?(Input::C)
      # Branch by command window cursor position
      case @command_window.index
      when 1  # skill
        # If this actor's action limit is 2 or more
        if $game_party.actors[@status_window.index].restriction >= 2
          # Play buzzer SE
          $game_system.se_play($data_system.buzzer_se)
          return
        end
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to skill screen
        $scene = Scene_Skill.new(@status_window.index)
      when 2  # equipment
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to equipment screen
        $scene = Scene_Equip.new(@status_window.index)
      when 3  # status
        # Play decision SE
        $game_system.se_play($data_system.decision_se)
        # Switch to status screen
        $scene = Scene_Status.new(@status_window.index)
      end
      return
    end
  end
end
#===============================================================================
# ** Window_Command_New
#-------------------------------------------------------------------------------
# This code allows the command window in the menu to display icons.
#===============================================================================

class Window_Command_New < Window_Selectable
  #-----------------------------------------------------------------------------
  # * Public Instance Variables
  #-----------------------------------------------------------------------------
  attr_reader :continue
  #-----------------------------------------------------------------------------
  # * Object Initialization
  #-----------------------------------------------------------------------------
  def initialize(index, continue)
    commands = [$data_system.words.item, $data_system.words.skill, $data_system.words.equip,
        'Status', 'Save', 'End Game']
    super(0, 0, 160, commands.size * 32 + 32)
    @item_max = commands.size
    @commands = commands
    self.contents = Bitmap.new(width - 32, @item_max * 32)
    refresh
    self.index = 0
  end
  #-----------------------------------------------------------------------------
  # * Draw Item
  #-----------------------------------------------------------------------------
  def draw_item(i, color)
    self.contents.fill_rect(0, i*32, 148, 32, Color.new(0, 0, 0, 0))
    bitmap = RPG::Cache.icon("Menu#{i}")
    opacity = (color == normal_color ? 255 : 128)
    self.contents.blt(4, 4 + i*32, bitmap, Rect.new(0, 0, 24, 24), opacity)
    self.contents.font.color = color
    self.contents.draw_text(28, i*32, 148, 32, @commands)
  end
  #-----------------------------------------------------------------------------
  # * Refresh
  #-----------------------------------------------------------------------------
  def refresh
    self.contents.clear
    for i in 0...@item_max
      draw_item(i, normal_color)
    end
  end
end
#==============================================================================
# ** Window_Gold
#------------------------------------------------------------------------------
#  This window displays amount of gold.
#==============================================================================

class Window_Gold < Window_Base
  #--------------------------------------------------------------------------
  # * Object Initialization
  #--------------------------------------------------------------------------
  def initialize
    super(0, 0, 160, 64)
    self.contents = Bitmap.new(width - 32, height - 32)
    refresh
  end
  #--------------------------------------------------------------------------
  # * Draw Picture
  #-------------------------------------------------------------------------- 
  def draw_picture(x, y)
    bitmap = RPG::Cache.picture("Coin")
    cw = bitmap.width
    ch = bitmap.height
    src_rect = Rect.new(0, 0, cw, ch)
    self.contents.blt(x, y, bitmap, src_rect)
  end
  #--------------------------------------------------------------------------
  # * Refresh
  #--------------------------------------------------------------------------
  def refresh
    self.contents.clear
    draw_picture(105, 4)
    cx = contents.text_size($data_system.words.gold).width
    self.contents.font.color = normal_color
    self.contents.draw_text(0, 0, 120-cx-2, 32, $game_party.gold.to_s, 2)
  end
end

Bumping now.