没有这样的文件加载 - rails（MissingSourceFile）...说什么？

在尝试将ThinkingTank gem包含到我的rails项目中时，我遇到了一个令人讨厌和奇怪的问题 . 当我在项目的Gemfile中包含 gem 'thinkingtank' 时，我收到以下错误：

~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require': no such file to load -- rails (MissingSourceFile)
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/thinkingtank-0.0.5/lib/thinkingtank.rb:1
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:in `require'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:in `require'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:in `each'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:in `require'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:in `each'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:in `require'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler.rb:112:in `require'
 from ~/git/myproject/config/boot.rb:121:in `load_environment'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/rails-2.3.5/lib/initializer.rb:137:in `process'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/rails-2.3.5/lib/initializer.rb:113:in `send'
 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/rails-2.3.5/lib/initializer.rb:113:in `run'
 from ~/git/myproject/config/environment.rb:9
 from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:254:in `require'
 from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:254:in `load_modules'
 from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:252:in `each'
 from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:252:in `load_modules'
 from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:21:in `setup'
 from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb.rb:54:in `start'
 from ~/.rvm/rubies/ree-1.8.7-2010.01/bin/irb:17

ruby -v 的输出是：

ruby 1.8.7 (2009-12-24 patchlevel 248) [i686-darwin10.6.0], MBARI 0x6770, Ruby Enterprise Edition 2010.01

rails -v 的输出是：

Rails 2.3.5

我遵循了their documentation和similar SA questions的基本准则 . 但是没有一个问题让rails gem失踪了..

是的，我们在Gemfile中包含rails =）

先感谢您 .