can set the web shield to personalized

I tried to set to personalized the web sheild to avoid browsing stop due to AVAST. I add the URL, then I set to personalized the scan web option. Otherwise it doesn’t work.
What happened. Is it due to the OS WinXP, or is it the Browser Firefox or somthing else ?javascript:void(0);
Huh

The order should be clicking the Customize buttom, add the URL (with wildcards if necessary) and just closing (and saving) the settings, without further changes.
But, are you sure you want to access an infected website?