gem_original_require:不需要加载这样的文件-spec/rails

gem_original_require': no such file to load -- spec/rails (MissingSourceFile)

我安装了以下与rspec相关的gems:

rails (2.3.8, 2.3.5)
rspec (2.0.1, 1.3.0, 1.2.9, 1.2.4)
rspec-core (2.0.1)
rspec-expectations (2.0.1)
rspec-mocks (2.0.1)
rspec-rails (2.0.1)

有什么办法解决这个问题吗?有趣的是,如果我将rails版本降到2.3.5(在environment.rb中),我会得到一个完全不同的错误:

Missing the Rails 2.3.5 gem. Please `gem install -v=2.3.5 rails`, update your RAILS_GEM_VERSION setting in config/environment.rb for the Rails version you do have installed, or comment out RAILS_GEM_VERSION to use the latest version installed.

感谢您的任何建议,