Problem with amavisd

Hi to all,
I'm testing a new server running Fedora8 with postfix-2.4.5,
dovecot-1.0.10, spamassassin-3.2.4, amavisd-new-2.5.2 and clamav-0.92.1.
Mails seems delivered correctly but sometimes with a delay about 5 minutes..
From Logwatch I read this warnings/errors but i don't know hot to solve
them.

60 Requesting process rundown after fatal error
60 TROUBLE in process_request: send failed in state 2: Pipe
rotta, fileno=12 at (eval ...
27 ClamAV-clamd: timed out, retrying (2) 27 WARN:
all primary virus scanners failed, considering backups
25 run_av (ClamAV-clamd, built-in i/f): Exceeded allowed time at
(eval 55) line 309.
18 ClamAV-clamd av-scanner FAILED: CODE(0x9cba5ac) Exceeded
allowed time at (eval 55) ...
17 Requesting process rundown, task exceeded allowed time during
waiting for input fro...
7 ClamAV-clamd av-scanner FAILED: CODE(0x9e9d540) Exceeded
allowed time at (eval 55) ...
2 ClamAV-clamd av-scanner FAILED: CODE(0x9e9d540) Too many
retries to talk to /var/sp...
2 run_av (ClamAV-clamd, built-in i/f): Too many retries to talk
to /var/spool/amavisd... Any ideas?Thanks in advance.. Flo.