Radiant-開発プラグインのrspecテストエラーの実行

エラーは次のとおりです.

/usr/local/system/ruby-1.8.7-p249/lib/ruby/gems/1.8/gems/radiant-0.8.2/vendor/rails/railties/lib/rails/gem_dependency.rb:119:Warning: Gem::Dependency#version_requirements is deprecated and will be removed on or after August 2010.  Use #requirement
Missing these required gems:
  rspec-rails  ~> 1.2.6
  webrat  ~> 0.4.4
  cucumber  ~> 0.3.9

これは、libバージョンが高すぎるため、次の文を実行します.

gem install rspec-rails -v 1.2.6
gem install webrat -v 0.4.4
gem install cucumber -v 0.3.9