I think you'll need to provide a few more details if you want some answers to this.. ie some code and maybe a description of what you are trying to do.

I'm guessing that your script reads in mail files of some description which are owned/readable by "mailman" in which case you will need to give "nobody" read access to these files. Just remember that any script running as nobody will have access to these files also.

Add some checks and error logging to your script wherever it accesses files and you'll probably find the problem.

suid perl allows scripts to run as different users for each virtualhost as specified in the Apache config. I get the feeling it won't help your current situation.

cheers,

J