Membership Plugin and Server Error

Ive set up a site using the Wordpress membership plugin and for some reason I keep getting a random server error. I have no idea as to what is causing this error as the site works fine but every now and then the server error is generated. The error generated is the following:

HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.

Has anyone seen this before?