After applied a advice from post of Malachy.Problem solved.
http://forum.avast.com/index.php?topic=26599.30Quote:
""To resolve these issues, you need to add two outbound rules:
1. Add avast.setup. For me the path is: "%ProgramFiles%\Alwil Software\Avast4\Setup\avast.setup"
2. Add ashWebSv.exe. For me the path is: "%ProgramFiles%\Alwil Software\Avast4\ashWebSv.exe"
Regarding number two, I am guessing (and this is just a guess here) that all web communications in or out (over ports 80, 443, 8080, etc...) pass through the Avast Web Shield...like a proxy. So if ashWebSv.exe is blocked then the result is like blocking your web clients (firefox, IE, etc...) ""
I never thought, i need to allow "ashWebSv.exe" for Avast Update.That was my bad.