title: AppCache mime type with IIS7
body: <p>We're hosting a couple of HTML5 games that utilise the <code>offline.appcache</code> feature letting games cache a lot better.</p>
  
  <p>To serve the <code>.appcache</code> type however, I had to add the mime type to the server (IIS7) so it wouldn't 404.  When I do, it refuses to serve any images or CSS files!  The error sent to the browser when I request a CSS or image file is:</p>
  
  <pre><code>The page cannot be displayed because an internal server error has occurred.
  </code></pre>
  
  <p>The extension I am adding is <code>appcache</code> with the MIME type <code>text/cache-manifest</code>.</p>
  
  <p>Any ideas why it's causing this behaviour?</p>