Firebytes - ditto, I've also applied everything you've done but all failed. I'll stay with Avast v5.x because w/o being able to check within PF options just too risky. I also have been using Avast for many many years and can't imagine starting to investigate which other av to use, a petrifying nightmare!
nmb - I originally understood that all going hunky-dory with Avast v6.x & PF on yr PC? Yes I've started a Support ticket with Avast and they have decided that the problem is with PF, their responses to me:
1st answer - "generally it is not recommended to use more than two antiviruses in one computer. I recommend you to use only one and uninstall the other. It causes such conflicts quite often."
2nd answer - "as I can see from their webpage
http://www.privacyware.com/personal_firewall.html it is antimalware as well"
I've not responded again because it seems case closed from Avast's point of view. The fact remains, from v6.x Avast sees PF as an "anti-virus / anti-malware" prog and therefore the clash.