Avast not automaticallyupdating virus def

Xp Home
SP2
Windows firewall activated
Latest version Avast (freeware) registered

Problem:
Avast does not appear to be automatically updating itself on either program or virus def. I Installed zonealarm temporarily to monitor outbound traffic and avast did not attempt to connect to any servers…however, when i updated manually the expected outbound traffic occured and the def file was updated without a problem…Zone alarm is not normally resident and i have added avast to the exceptions list in the windows firewall. Could it be the websvr.exe and ashsvr.exe that i need to add to the exception list too…

Any suggestions folks?

Yes see this thread for a list of services to be allowed access http://forum.avast.com/index.php?topic=13258.0