Hi there, I was trying to use both Ruby 1.8.6 and Ruby 1.9.1 on my laptop. After I install Ruby 1.9.1, I went back to my Ruby 1.8.6, and run : Ruby script/server. I got the following error: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/ 1.8/rubygems/custom_require.rb:27:in `gem_original_require'': no such file to load -- uuid (MissingSourceFile) Maybe it could not fine the file, how can I fix this? Thank you very much!