When I type and names of the files you mentioned I get the following output.

irb(main):001:0> type-windows.mgk
(irb):1: warning: Object#type is deprecated; use Object#class
NameError: undefined local variable or method `windows' for main:Object
        from (irb):1
irb(main):002:0> RMagick.rb
NameError: uninitialized constant RMagick
        from (irb):2