title: undefined method `source_index' for Gem:Module (NoMethodError)
body: <p>I'm running a Rails 2.3.5 application and upon running script/server I am shown the following:</p>
  
  <pre><code>./script/../config/../vendor/rails/railties/lib/rails/gem_dependency.rb:21:in `add_frozen_gem_path': undefined method `source_index' for Gem:Module (NoMethodError)
      from ./script/../config/boot.rb:60:in `load_initializer'
      from ./script/../config/boot.rb:44:in `run'
      from ./script/../config/boot.rb:17:in `boot!'
      from ./script/../config/boot.rb:123
      from script/server:2:in `require'
      from script/server:2
  </code></pre>
  
  <p>If I comment out line 60 in boot.rb (Rails::GemDependency.add_frozen_gem_path) and run script/server, I get this:</p>
  
  <pre><code>=&gt; Booting WEBrick
  =&gt; Rails 2.3.5 application starting on http://0.0.0.0:3000
  ./script/../config/../vendor/rails/railties/lib/rails/gem_dependency.rb:21:in `add_frozen_gem_path': undefined method `source_index' for Gem:Module (NoMethodError)
      from ./script/../config/../vendor/rails/railties/lib/initializer.rb:298:in `add_gem_load_paths'
      from ./script/../config/../vendor/rails/railties/lib/initializer.rb:132:in `process'
      from ./script/../config/../vendor/rails/railties/lib/initializer.rb:113:in `send'
      from ./script/../config/../vendor/rails/railties/lib/initializer.rb:113:in `run'
      from /home/developer/bigpink/config/environment.rb:13
      from /home/developer/bigpink/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require'
      from /home/developer/bigpink/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require'
      from /home/developer/bigpink/vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in'
      from /home/developer/bigpink/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require'
      from /home/developer/bigpink/vendor/rails/railties/lib/commands/server.rb:84
      from script/server:3:in `require'
      from script/server:3
  </code></pre>
  
  <p>So, not really sure what to do. Hoping I can get some quick help. Thanks!</p>