title: Could not find RubyGem rails (>= 0) (Gem::LoadError)
body: <p>I am creating a website using Ruby on Rails 3. I have been working on this project for 2 months and everything was working fine. Suddenly I get the following error after I added the gem 'ckeditor', '3.4.2.pre' to my gemfile. I followed  the ckeditor tutorial here: <a href="http://hafizbadrie.wordpress.com/2011/07/31/rails-3-and-ckeditor/" rel="nofollow">http://hafizbadrie.wordpress.com/2011/07/31/rails-3-and-ckeditor/</a>  and everything worked fine but since then  whenever I run any command like rails server or bundle install on my console I get the following error:</p>
  
  <hr>
  
  <pre><code>WARNING:  Invalid .gemspec format in '/usr/lib/ruby/gems/1.8/specifications/arel-0.3.3.gemspec'
  /usr/local/lib/site_ruby/1.8/rubygems.rb:777:in `report_activate_error': Could not find RubyGem rails (&gt;= 0) (Gem::LoadError)
      from /usr/local/lib/site_ruby/1.8/rubygems.rb:211:in `activate'
      from /usr/local/lib/site_ruby/1.8/rubygems.rb:1056:in `gem'
      from /usr/bin/rails:18
  </code></pre>
  
  <p>I searched on Google and got a solution saying run gem install bundler but that did not solve my error. Because of this error I am not able to proceed further since not a single command is running.</p>
  
  <p>How can i solve this error?
  thanks in advance...</p>