What must be done besides installation?

Comodo Firewall v2 failed the three CLIP tests on my system so I removed v2 and installed v3.0.15.277. But when I ran the CPIL tests again, it failed the three tests.

I wonder if there is something else that I must do besides installing the firewall?

Thanks.

Win XP Sp2
IE 7 and Firefox 2.0.0.11
Avast Antivirus
Dial-up connection