On Sep 3, 2009, at 16:28, Derek Mailer wrote:

> ERROR:  While executing gem ... (NoMethodError)
>    undefined method `ruby_version' for Gem:Module
>        ./lib/rubygems/commands/setup_command.rb:62:in
> `check_ruby_version'
>        ./lib/rubygems/commands/setup_command.rb:100:in `execute'
>        /usr/local//lib/ruby/site_ruby/lib/rubygems/command.rb:136:in  
> `invoke'

Whoah!  How'd you load up your system RubyGems?

setup.rb re-exec's itself if it see RUBYOPT is set to load installed  
RubyGems, but it seems that you're escaping this check somehow.

After the three require 'rubygems' in setup.rb can you add:

   p $", $:

I'd like to see where/how your installed rubygems is getting loaded.