Even I as administrator get the following error when trying to send mail from the forums.

The server encountered an unexpected condition which prevented it from fulfilling the request.The script did not produce correct headers. It must at least print out a Content-Type header, like so:
Content-Type: text/html

The header the script produced was:
HTTP/1.1 200 OK

Does anyone know which script (pm file?) I need to check to see what's going on? I've tried all forms of email setup on the site and it made no difference. This use to work fine for nearly two years (lots of subscription emails and private emails all worked fine) but for some reason now I get this error and people do not seem to be recieving back validation emails when signing up.

HELP!!!!