 <p>This error means that <code>Rails.application</code> isn't initialized. I didn't actually know that, <a href="https://github.com/rails/rails/blob/v3.0.8/railties/lib/rails/commands.rb#L29" rel="nofollow">I cheated</a>.</p> <p>So that then begs the question: how did you set up this application?</p> <p>Perhaps this application doesn't contain a <code>config/application.rb</code> file that defines a class that inherits from <code>Rails::Application</code> and therefore is causing this problem. In my application here, I've got <a href="https://github.com/rails3book/ticketee/blob/master/config/application.rb" rel="nofollow">this one</a> you could use as an example.</p>