What's causing "support for RegExp patterns is deprecated" error?

railer:sphinx railer$ script/generate scaffold Dummy
Gem::SourceIndex#search support for Regexp patterns is deprecated
/Library/Ruby/Gems/1.8/gems/rails-2.1.1/lib/rails_generator/lookup.rb:211:in `each' is outdated
       exists app/models/
       exists app/controllers/

...

railer:sphinx railer$ script/generate scaffold Dummy
Gem::SourceIndex#search support for Regexp patterns is deprecated
/Library/Ruby/Gems/1.8/gems/rails-2.1.1/lib/rails_generator/lookup.rb:
211:in `each' is outdated
      exists app/models/
      exists app/controllers/

rubygems 1.3 is brand new, sounds like they've deprecated something that current versions of rails use. It's not an error, it's a warning that future versions of rubygems won't support this (and that rails should be fixed accordingly)

Fred