Issue with KGC EquipExtension

This is the line I get the error at:
Line 975

Code: [Select]

  def update_item_windows
    kind = equip_kind(@equip_window.index)
    for i in 0...EQUIP_TYPE_MAX
      @item_windows[i].visible = (kind == i)
      @item_windows[i].update
    end
    @item_window = @item_windows[kind]
    @item_window.simple_refresh(@equip_window.index)
  end
  #--------------

The Error:
Undefined Method "simple_refresh"

I've created numerous new equipment slots and it should be noted that the error only occurs when I scroll to the bottom of the equipment list and try to scroll down further.  Or when I try to scroll up from the top.   That is, it will scroll down until all equip slots are visible, but then it delivers the error if I try to scroll further down.