Problem with Formmail

Hi,
I am using formmail.pl and have saved it to my cgi bin. I have a form that
points towards the file. When I click send I get the following message
"CGI Error
The specified CGI application misbehaved by not returning a complete set of
HTTP headers."
Can any body suggest some possible solutions.
I am new to this form sending stuff and need all the help I can get.
Thanks