[Plugin: Primary Feedburner] Multisite broken

I enbled this plug in set up feedburner account hit save and now i get the following message and cant enter my site. i guess this is going to take days to fix.
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 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Apache Server at southernwebdesign.co.uk Port 80