Internal Server Error

I have a CPanel server running PHP 5.4 and I installed webform on one site and I can create the webform but when I want to add components I get a 500 Internal server error. I read somewhere it has to do with FastCGI but my server is configured as SuPHP.

Please can you help me

I get the following warning so maybe this can be related to the error:

Warning: uasort() expects parameter 2 to be a valid callback, no array or string given in webform_components() (line 4572 of /home/skree/public_html/sites/all/modules/webform/webform.module).