I have the same problem.
I have zimbra Release 6.0.9_GA_2686.UBUNTU8 UBUNTU8 FOSS edition.
and i got following error in morning
zimbra@mail:/$ zmcontrol restart
Host mail.investcare.in
Stopping stats...Done.
Stopping mta...Done.
Stopping spell...Done.
Stopping snmp...Done.
Stopping archiving...Done.
Stopping antivirus...Done.
Stopping antispam...Done.
Stopping imapproxy...Done.
Stopping memcached...Done.
Stopping mailbox...Done.
Stopping logger...Done.
Stopping ldap...Done.
Host mail.investcare.in
Starting ldap...Done.
Starting logger...Done.
Starting mailbox...Done.
Starting memcached...Done.
Starting antispam...Done.
Starting antivirus...Failed.
Starting zmmtaconfig...zmmtaconfig is already running.
Starting amavisd...amavisd is already running.
cp: cannot stat `/opt/zimbra/clamav/db/daily.cvd.init': No such file or directory
cp: cannot stat `/opt/zimbra/clamav/db/main.cvd.init': No such file or directory
Starting freshclam...done.
Starting clamd...LibClamAV Warning: ************************************************** *********
LibClamAV Warning: *** This version of the ClamAV engine is outdated. ***
LibClamAV Warning: *** DON'T PANIC! Read
http://www.clamav.net/support/faq ***
LibClamAV Warning: ************************************************** *********
connect(): Connection refused
failed.
Starting snmp...Done.
Starting spell...Done.
Starting mta...Done.
Starting stats...Done.
Permission on the directory /opt/zimbra/clamav/db is for zimbra user