title: HTTP Error 500 when attempting to access localhost
body: <p>I just built my first "web app" for a class using Google App Engine, and it deployed correctly, and works perfectly well on Google's servers. However, when I try to access it on localhost, I get a 500 error:</p>
  
  <p>"Server error The website encountered an error while retrieving <a href="http://localhost:8081/" rel="nofollow">http://localhost:8081/</a>. It may be down for maintenance or configured incorrectly."</p>
  
  <p>I have tried using various ports, and none of them seem to work. I am 100% positive I am using the correct port and that the app is actually running with no errors.</p>
  
  <p>I am using Google Chrome and Python 2.7.2 on Mac OS 10.6.8</p>
  
  <p>Any ideas on how to correct this or what configurations to check?</p>