title: Why do I get "Could not find 'railties' error with Rails server?
body: <p>When I start my Rails server using  <code>rails s</code>, I getting this error:</p>
  
  <pre><code>/usr/local/lib/site_ruby/1.8/rubygems/dependency.rb:296:in `to_specs': Could not find 'railties' (&gt;= 0) among 10 total gem(s) (Gem::LoadError)
  from /usr/local/lib/site_ruby/1.8/rubygems/dependency.rb:307:in `to_spec'
  from /usr/local/lib/site_ruby/1.8/rubygems/core_ext/kernel_gem.rb:47:in `gem'
  from /usr/bin/rails:22
  </code></pre>
  
  <p>How do I fix it?</p>