New mail accounts not working

[macworks]

I have a couple dozen mail accounts on a xServe server that I manage. The server was running 10.4.5 until I updated 10.4.6. Under either version, new mail accounts would not work. Mail software would fail to retrieve messages from the server. When I send mail to the accounts, they don't bounce back nor do they get delivered into the users mailbox (according to Server Admin > Mail > Maintenance > Accounts

All of the old accounts are still working normally. I've tried creating several accounts and none of the new ones will work. Do I have to set aside my entire Mail store in order to get this to work again?

I've tried deleting and recreating the accounts via Workgroup Manager, but this never actually deletes the mail user account located in /email-store/mail/user

I've also tried various methods for fixing and rebuilding the mailbox / mail database and had no luck. I've tried logging into Cyrus and attempted to delete the offending mail accounts, but get no where with that either.

Any suggestions?