I'm having what seems to be the same problem as the other people who've written here - I wonder whether you or anyone else has discovered a solution yet? The build error (this is with the stub 'puts' lines in Controller.rb) is:

/Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/objc/oc_import.rb:22:in `module_eval': undefined method `NSClassFromString' for OSX:Module (NoMethodError)

	from /Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/objc/oc_import.rb:21:in `module_eval'

	from /Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/objc/oc_import.rb:21:in `ns_import'

	from /Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/objc/foundation.rb:5

	from /Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/objc/cocoa.rb:11:in `require'

	from /Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/objc/cocoa.rb:11

	from /Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/cocoa.rb:11:in `require'

	from /Library/Frameworks/RubyCocoa.framework/Versions/A/Resources/ruby/osx/cocoa.rb:11

	from /Users/leeg/devel/Cocoa/RubyTar/build/RubyTar.app/Contents/Resources/rb_main.rb:9:in `require'

	from /Users/leeg/devel/Cocoa/RubyTar/build/RubyTar.app/Contents/Resources/rb_main.rb:9

Some potentially useful configuration information:

mallet:~ leeg$ ruby -v

ruby 1.8.2 (2004-07-29) [powerpc-darwin7.5.0]

mallet:~ leeg$ uname -a

Darwin mallet.local 7.5.0 Darwin Kernel Version 7.5.0: Thu Aug  5 19:26:16 PDT 2004; root:xnu/xnu-517.7.21.obj~3/RELEASE_PPC  Power Macintosh powerpc

XCode 1.5

Component versions

Xcode IDE: 389.0

Xcode Core: 387.0

ToolSupport: 372.0

I did a cvs up on rubycocoa to make sure that the problem persisted, just before posting this message. Indeed it does. Thanks, leeg.