Horatio:~ Rahul$ sudo gem install rails --include-dependencies Attempting local installation of 'rails' Local gem file not found: rails*.gem Attempting remote installation of 'rails' Updating Gem source index for: http://gems.rubyforge.org Successfully installed rails-1.0.0 Successfully installed rake-0.6.2 Successfully installed activesupport-1.2.5 Successfully installed activerecord-1.13.2 Successfully installed actionpack-1.11.2 Successfully installed actionmailer-1.1.5 Successfully installed actionwebservice-1.0.0 Installing RDoc documentation for rake-0.6.2... lib/rake.rb:733:18: unexpected token: '#<RubyToken::TkLPAREN:0x515748 @text="(", @char_no=7, @line_no=733>' Installing RDoc documentation for activesupport-1.2.5... Installing RDoc documentation for activerecord-1.13.2... Installing RDoc documentation for actionpack-1.11.2... lib/action_controller/code_generation.rb:77:31: unexpected token: '#<RubyToken::TkLPAREN:0x2fdaee8 @text="(", @char_no=19, @line_no=77>' lib/action_controller/code_generation.rb:168:31: unexpected token: '#<RubyToken::TkLPAREN:0x104f180 @text="(", @char_no=19, @line_no=168>' ERROR: While executing gem ... (NoMethodError) undefined method `find_module_named' for nil:NilClass
1.8.3 makes it all better :-)