I've noticed that davmail stopped working on debian unstable recently.
WIRE debug output shows just an irritating:
2010-01-05 08:48:09,027 INFO [AWT-EventQueue-0] davmail - DavMail Gateway 3.6.1-853 listening on
2010-01-05 08:48:09,028 ERROR [AWT-EventQueue-0] davmail - Unable to bind server socket...
2010-01-05 08:00:30 UTC in DavMail POP/IMAP/SMTP/Caldav to Exchange