I am no perl expert either, but this may be happening because you are requiring Mailer.pm in the script. If you have the default Mailer.pm that sends in text format. I have altered my Mailer.pm to send html. Search under my username and html and you will find the code for changing it. I posted it about 5 or 6 months ago. I have also forwarded an example of the emails that are sent to my users to you.

Jimmy Crow
http://www.homewithgod.com/