Im trying to move one of my clients from ensim to cPanel, but his formmail.pl script doesnt seem to work anymore, it just throws up an error 500 page

i know cpanel has its own formmail.pl script, but seeing as tho it appears to be encoded, i would rather use this one, as i can limit the e-mail address's that it can send to......

Ive tried everything that i can think of... including a possible binary/ascii problem etc

Any other suggestions?