Drupal mailhandler module and Mac OS X Tiger Server

I recently upgraded a box at work to Tiger Server (Mac OS X 10.4) and for some reason the Drupal mailhandler module doesn't want to collect mail. PHP seems to be functioning OK and no error is logged by the system. I even had it log PHP notices and still nothing. The module seems to work just fine in picking up mail from a box running a different mail server so I'm guessing it is something to do with the mail server in OS X Tiger. However the mail server doesn't report any login attempt.

How very odd....