MyBB Help (+rep)

Hi, ive just set up a MyBB forum but when i go on it it comes up with this:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, [email protected] and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request. Apache/1.3.34 Server at www.habhop.co.uk Port 80


Ive changed the permission but it still wont work, does anyone know whats wrong with it?
+rep to those that help
Thanks