You should not block this as you can read here: http://www.shouldiblockit.com/avastemupdate.exe-74c470d8fa1fb9c025ecbf7964fd1a59.aspx
Here the FP, a general heuristic virus detection for Gen:Variant.Zusy.22497, isbeing discussed: http://forums.iobit.com/showthread.php?t=14316
poster of thread = Buddahfan

polonus