title: Clean Yeoman install results in a Grunt error
body: <p>I am running <code>grunt server</code> after a clean install of Yeoman, using the Webapp generator and I get the following error:</p>
  
  <p><code>Warning: Errno::ENOENT on line 441 of /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/pathname.rb: No such file or directory - /Users/nfento/Sites/test/app/bower_components
      Run with --trace to see the full backtrace Use --force to continue.</code></p>
  
  <p>Any idea what would be causing this? I have been able to reproduce the error on two machines. I'm completely new to using grunt, but have used it as a server with livereload previously.</p>