I hate trying to read MOG scripts. I don't see why they can't index their scripts. Further, they always use pictures. That makes it graphically nice, but it also means that I have to hunt down 100 pictures just to test the script.
Anyway, enough venting.
Try changing this line:
@command_window = Window_Command.new(172, [s1, s2, s3])
to
@command_window = Window_Command.new(172, [s1, s2, s3], 3)
and report back to me.