title: "A promise chain failed to handle a rejection" while loading add-on
body: <p>I'm developing a Firefox add-on with content scripts that include jquery, <a href="https://github.com/groovecoder/firefox-addon/blob/codesy-js-refactor/data/codesy.js" rel="nofollow">a single script containing my code object</a>, and <a href="https://github.com/groovecoder/firefox-addon/blob/codesy-js-refactor/data/launch.js" rel="nofollow">a launch script</a> to activate the class when the window location matches certain patterns:</p>
  
  <p><a href="https://github.com/groovecoder/firefox-addon/tree/codesy-js-refactor" rel="nofollow">https://github.com/groovecoder/firefox-addon/tree/codesy-js-refactor</a></p>
  
  <p>Whenever I launch Firefox with this add-on, I get a strange error that seems to come from the Add-on SDK itself?</p>
  
  <pre><code>20:58:23.165 XPIDatabase.connection is undefined main.js:42
  20:58:23.228 [object Object] runner.js:162
  20:58:23.232 [object Object] promise.js:133
  20:58:33.346 A promise chain failed to handle a rejection.
  
  Date: Sat Jan 25 2014 20:58:23 GMT-0600 (CST)
  Full Message: Unix error 17 during operation makeDir (File exists)
  </code></pre>
  
  <p>No part of my add-on executes - even an <code>alert("Hello")</code> at the very beginning of <code>lib/main.js</code> is never reached or executed.</p>