Incoming mail suddenly stoppped

I have an 10.6 email server set up that suddenly stopped incoming mail to all accounts with errors similar to this one below in the mail.log:

May 30 14:05:36 mail postfix/error[1633]: 18B223F7417: to=<fakeuser@procommss.com>, relay=none, delay=16537, delays=16530/6.5/0/0.22, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to 127.0.0.1[127.0.0.1]:10024: Connection refused)

I purposefully hold Software Update back for manual updates so I can have a backup before I run the updates so I know it wasn't an Apple update that made this happen. The server had been running fine until yesterday morning and had undergone no changes or modifications leading up to this problem although, after finding this problem, I did proceed with an Apple Software Update that brought the server up to the latest updates.

This server underwent the spamtrainer installation and custom settings outlined on osx.topicdesk.com when I first put it online but has had no other "mods" done on it. It's a pretty standard box.

Toggling the "Enable Junk Mail Filtering" tick box in Server Admin seemed to clear the problem up but when I do so, I still see activity in the amavis log.

The server is working now delivering received mail but I'd like everything working properly and I'm not sure that is the case now. Where should I start looking? I'd be glad to post whatever logs might be of help.