pHp mailing list problem,

[globalcashsite]

Guys

I installed built-in php mailing list from Fantastico at http://globalcashsite.com/mailinglist/ but this is giving error

Internal Server Error

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

Please contact the server administrator, webmaster@globalcashsite.com 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.

Any idea how I can solve this problem, my site is working fine.

GCS