Hi bnnnjc485,
Send the webmaster of the site an e-mail and explain your situation, and ask why you are being blocked or cannot access their server(s).
Could be they restricted a complete IP-range there, because some-one there did something "out of line" or they block/restrict the avast shields user agent for some reason or other, as they see it as conflicting like with some scanning agents and the way they interfere there policy, recently saw a conflict in this line with AVG LinkScanner and webmasters complained...
These things happen, can be solved through a mail and you will stay "the best of friends",
polonus