title: ruby new create error, unable to understand
body: <p>I'm new to ruby on rails, and am planning to learn it.</p>
  
  <p>However I'm unable to understand the following error.</p>
  
  <p>Please explain me. Also tell me how to resolve it.</p>
  
  <p>This is the command I ran, </p>
  
  <pre><code>rails new Documents/rails/first/
  </code></pre>
  
  <p>This is the error:</p>
  
  <pre><code>/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:230:in `activate': can't activate rack (~&gt; 1.4.5, runtime) for ["actionpack-3.2.13", "railties-3.2.13"], already activated rack-1.5.2 for ["rack-ssl-1.3.3", "railties-3.2.13"] (Gem::LoadError)
          from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:246:in `activate'
          from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:245:in `each'
          from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:245:in `activate'
          from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:246:in `activate'
          from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:245:in `each'
          from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:245:in `activate'
          from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:1056:in `gem'
          from /usr/bin/rails:18
  </code></pre>