run RailsServer on aptana studio 3

hi i want to run my ruby application on aptana studio 3.0 : when i run the railsserver i have this message : C:/Ruby200/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:106:in `require': cannot load such file -- initializer (LoadError)   from C:/Ruby200/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:106:in `require'   from C:/Dev/Aptana/bibliotheque/config/boot.rb:55:in `load_initializer'   from C:/Dev/Aptana/bibliotheque/config/boot.rb:38:in `run'   from C:/Dev/Aptana/bibliotheque/config/boot.rb:11:in `boot!'   from C:/Dev/Aptana/bibliotheque/config/boot.rb:110:in `<top (required)>'   from C:/Ruby200/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require'   from C:/Ruby200/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require'   from C:/Dev/Aptana/bibliotheque/script/server:2:in `<main>'

Have you an idea?