MenuEngine

MenuEngineをインストールしようとしたがエラーになりインストールできない。
EclipseのRails PluginsからMenuEngineを選択しGoボタンを押下するとエラーになってしまう。
リポジトリーが見つからないようだ。

./script/../config/boot.rb:29:Warning: require_gem is obsolete. Use gem instead.
Plugin not found: ["http://svn.rails-engines.org/plugins/menuengine"]
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:422:in `remove_const': cannot remove Object::Verbose (NameError)
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:422:in `send'
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:422:in `remove_constant'
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:368:in `new_constants_in'
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:368:in `each'
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:368:in `new_constants_in'
from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:495:in `require'
from script/plugin:3