I found /private/etc/spam/clamav/clamd.conf where it states that socket is /tmp/clamd.
clamd itself is not running and there is no socket for clamd.
amavis is a milter (sendmail or postfix plugin). Since you're running CGP, you probably don't need amavis running. Do you have a clamd process running? If so, you'll need to figure out where its socket is located (default is in /tmp, but who knows where Apple decided to store it). Try to find the clamd.conf file, that should tell you where clamd's socket is.
Is anyone using ClamAV that ships with Mac OS X Server? It can be updated daily by a few clicks in Server Admin.
I would like to use cgpav to connect to built-in ClamAV of Mac OS X Server. After starting the AV-Software, I find amavis processes. I'm not sure what these are about and how to connect cgpav to amavis or clamav.