Was broken for me as well so had a play and got it working again.
The plug-in relies on the jQuery library which is not included in the plug-in itself and if this library isn’t called in your theme then it won’t work.
Here’s what I did:
Go into your theme, find header.php and call up jQuery somewhere between the head tags; the best and easiest way is to use Google’s hosted code.
e.g, paste in the following:
<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js'></script>
Make sure your theme isn’t calling up jQuery elsewhere or another Java library that will cause a conflict.
