As mentioned earlier, I used to use PCT FW alongside with avast! on Windows 7 on the same machine with no changes whatsoever. The only difference is that my current installation, if it can be called such, has Service Pack 1 installed, and my previous one didn’t. At the moment I’m using Windows FW with avast! AV without any problems.

I should have mentioned that I reformatted my PC prior to the latest version of avast! was released, while it might be a possibility, although highly unlikely, that the latest version of avast! AV isn’t compatible with the latest version of PCT FW.

Thanks for the advice on other firewall programs, SafeSurf.