[otrs] Internal server error when OTRS trying to send mail

OTRS is setup and working pretty much...but whenever I try to get it to do anything that needs to send mail out (eg. send lost password, reply to customer, etc.) it just gives an apache internal server error. It's running on Win2000 with mysql and apache. We are using an external SMTP server, and the username, server and password for the SMTP are configured in the config.pm file. Any ideas? Justin