Unable to get X-Lite VOIP application to work


I am trying out Comodo Antivirus and firewall. I use X-Lite VOIP. Ever since I loaded Comodo antivirus, X-Lite crashes after a call is initiated (after varying amounts of time, sometimes 2 seconds, sometimes 10). It works ok with other firewalls (Zone Alarm) and other anti-virus products (ClamWin). I know it is not the Comodo Firewall, because X-Lite ran ok with the firewall, but when I added the anti-virus, the problem started.

Thanks in advance,