Suspicious Message alert keeps popping up

[CaptainKen]

"avast! Virus warning Suspicious Message!" keeps popping up while trying to download from newsgroups with Newsbin. When I click Continue they just keep coming back. The Block it and Permitted URL's buttons are grayed out. Yes I'm logged in as Admin on Windows XP Pro SP2 machine. I should also mention this only happens on some nbz downloads.

The only way to stop it is to Stop On-Access protection.

[alanrf]

Newsgroup downloads are scanned by the Internet Mail provider. 

What is the sensitivity setting you have for that provider?

[CaptainKen]

Assuming it is the settings in Internet Options, Privacy - the setting is Medium. This is the same setting that I successfully when I had Norton.

[DavidR]

No Alan is asking for the avast Internet Mail provider sensitivity setting.

[Lisandro]

"avast! Virus warning Suspicious Message!"

This is a message from the Heuristic module of Internet Mail provider.
You can configure the settings. Let the level on Custom and go to the Heuristic tabs (there are two).
Configure them as you need 

The only way to stop it is to Stop On-Access protection.

No... you don`t have to do that and stay without antivirus protection.
Just configure avast as you need/want 

[CaptainKen]

Thanks everyone for responding.

Mine is set to Medium, so I changed it to Low. So why were the "Block it" and "Permitted URL's" buttons are grayed out and how do it ungray them.

BTW, man is that setting hidden. "avast! On Access Sanner", Details, Internet Mail, Customize, Heuristics.  Just by eliminating the "Details" option and having it be the default would make this 10 times easier to find.