Double check the the PHP and MySQL Versions on the server. they should be PHP 5.2+ an MySQl 5+
also:
in the webassist/kfm/index.php page
find the following line:
<script type="text/javascript" src="j/all.php/can-minify"></script>
and change it to:
<script type="text/javascript" src="j/all.php"></script>