no such file to load -- opendirectory/user

Hello everyone,
I encountered a problem when i launch a Rails Application with "Run
as" in RadRails.

It is not a problem on my project but on the installation of RadRails
or the gem package or Ruby On Rails... I am lost !

This is the message created in the console :

"13580"
=> Booting Mongrel (use 'script/server webrick' to force WEBrick)
=> Rails application starting on http://0.0.0.0:3001
=> Call with -d to detach
=> Ctrl-C to shutdown server
** Starting Mongrel listening at 0.0.0.0:3001
** Starting Rails with development environment...
** Rails loaded.
** Loading any Rails specific GemPlugins
** Signals ready. TERM => stop. USR2 => restart. INT => stop (no
restart).
** Rails signals registered. HUP => reload (without restart). It
might not work well.
** Mongrel 1.1.4 available at 0.0.0.0:3001
** Use CTRL-C to stop.

Processing Base#index (for 127.0.0.1 at 2010-03-02 08:45:07) [GET]
  Session ID: 88ed1b808ed9394daa8279d902efd3aa
  Parameters: {}

MissingSourceFile (no such file to load -- opendirectory/user):
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/1.8/rubygems/custom_require.rb:27:in `require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:495:in `require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:342:in `new_constants_in'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:495:in `require'
    /Users/clementfarrugia/Documents/Aptana RadRails Workspace/
pcastserv/app/controllers/application.rb:14
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:203:in `load_without_new_constant_marking'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:203:in `load_file'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:342:in `new_constants_in'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:202:in `load_file'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:94:in `require_or_load'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:60:in `depend_on'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:442:in `require_dependency'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/rails-1.2.6/lib/dispatcher.rb:109:in
`prepare_application'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/rails-1.2.6/lib/dispatcher.rb:39:in `dispatch'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/bin/../lib/mongrel/rails.rb:76:in
`process'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/bin/../lib/mongrel/rails.rb:74:in
`synchronize'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/bin/../lib/mongrel/rails.rb:74:in
`process'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:159:in
`process_client'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:158:in `each'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:158:in
`process_client'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:285:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:285:in `initialize'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:285:in `new'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:285:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:268:in `initialize'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:268:in `new'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel.rb:268:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel/configurator.rb:282:in
`run'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel/configurator.rb:281:in
`each'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel/configurator.rb:281:in
`run'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/bin/mongrel_rails:128:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/lib/mongrel/command.rb:212:in `run'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/mongrel-1.1.4/bin/mongrel_rails:281
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:488:in `load'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:488:in `load'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:342:in `new_constants_in'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:488:in `load'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/rails-1.2.6/lib/commands/servers/mongrel.rb:60
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/1.8/rubygems/custom_require.rb:27:in `require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:495:in `require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:342:in `new_constants_in'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/activesupport-1.4.4/lib/active_support/
dependencies.rb:495:in `require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/gems/1.8/gems/rails-1.2.6/lib/commands/server.rb:39
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
ruby/1.8/rubygems/custom_require.rb:27:in `require'
    ./script/server:3
    -e:2:in `load'
    -e:2

Rendering /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/
lib/ruby/gems/1.8/gems/actionpack-1.13.6/lib/action_controller/
templates/rescues/layout.rhtml (500 Internal Error)

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