I found a problem with WebShield last night also. I actually noticed the problem several days ago but because it's related to something I don't do daily it wasn't at the top of my investigation list.
The problem is related to me accessing some company web pages via VPN. I could get into my company's domain and access almost everything I need to with one glaring exception. There was one page in particular that I suddenly could no longer access. Because of the error I was getting, "web page or server unavailable", "possible DNS issue", etc., I strongly assumed a firewall problem but I eliminated that possibility by un-installing the firewall.
The way I finally determined it was WebShield related was by terminating all Avast modules and trying to access the web page in question.....it worked again!
So I started turning on each module and trying the same page again. It worked each time until I restarted the WebShield.
I tried putting the page in question in the WebShield "Exceptions" list but it seems that function has a problem also.
The web page I was trying to add to "Exceptions" was an "https" page and you apparently can't add those. When I typed in the page "https://*******" Avast automatically added the prefix "http", so it ended up being "
http://https://******"
Obviously that wouldn't work so I finally gave up, terminated the WebShield module and now I can access everything again.
I am using Windows XP Professional, SP2