I also noticed the problem. When using FF i was able to pull the data from e.response but in IE it was not working. After searching in their source JS found the problem. There is a problem with getting the response from the hidden iframe they use to upload the files. In order to fix it find:
and replace it with :
If you are using the non-minified version find:
responseText = iframe.contents().text();
and replace with:
responseText = iframe.contents().find(
This will now work with both IE9 and FF (have not tested for backward compatibility with older versions of IE though).