[Dovecot] LDA alias resolution problems..

[Nick Warr]

I use postfix + dovecot LDA + mysql virtual users and up til friday, 
everything was working just fine.

Dovecot is 2.0.beta6 (3156315704ef)

Like I said, up til friday, when I added a vacation entry into postfix 
(which I have now removed to see if it was the reason) mails to the 
alias virusalert (which is aliased to me) went through just fine.

Now I get these sort of errors from the LDA:

Feb 27 11:54:03 cluster2 postfix/pipe[31267]: 866F0A41173: 
to=<virusalert at mobilia.it>, relay=dovecot, delay=357414, 
delays=357413/0.79/0/0.05, dsn=4.3.0, status=deferred (temporary 
failure. Command output: lda: Fatal: Unknown user )


Other aliases work perfectly, the only difference is that these emails 
are of local origin, (they're messages from Amavisd) I'm not sure why 
this has started to be a problem.

Can anyone give me an idea where I should start looking?

Nick