Unable to start Mongrel after Rubygem update

[djee]

The bug appaear after having update the rubygems with command: gem update --system

Environment:
OSX 10.6
Ruby 1.8.7 p334
Rubygems:1.6.2
Rails 2.2.2

=> Booting Mongrel (use 'script/server webrick' to force WEBrick)
=> Rails 2.2.2 application starting on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/Users/dumas/.rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking': no such file to load -- mongrel_rails (MissingSourceFile)

Stack trace
from .rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in load' from .rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:innew_constants_in'
from .rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in load' from .rvm/gems/ruby-1.8.7-p334/gems/rails-2.2.2/lib/commands/servers/mongrel.rb:64 from .rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:ingem_original_require'
from .rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in require' from .rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:inrequire'
from .rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in new_constants_in' from .rvm/gems/ruby-1.8.7-p334/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:inrequire'
from .rvm/gems/ruby-1.8.7-p334/gems/rails-2.2.2/lib/commands/server.rb:49
from .rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in gem_original_require' from .rvm/rubies/ruby-1.8.7-p334/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:inrequire'
from script/server:3