When enabling AV/AS, on a certain server (5.0, upgraded to last version today) I have a runnig problem wih AMAVISD: amavisd runs on 100% processor, and seems to hang continuously. All mail is getting deferred as it cannot be passed from postfix to amavis. Disabling AV/AS is a workaround, but as this issue remains in 5.0, I'd like to find a solution.

I have been searching different fora, bugzilla's, wiki's, but I'm afraid I can't seem to find any solution on why this is happening. I already enabled some verbose loggings (smtp -v from postfix to amavis, log_level 5 in amavis), but this does not give any extra info on why Amavis itself is running loose.

Code:
Jan  4 17:00:05 deepthroat postfix/qmgr[6005]: 5EC4F584E1: to=, relay=none, delay=0.14, delays=0.12/0.02/0/0, dsn=4.3.0, status=deferred (mail transport unavailable)
Any pointers on how to start troubleshoting this?