Error in Web Shield. False Positive Infection:Win32:Evo-gen [Susp]

Hello every body!
At 8h AM. I receive a warning from Avast! Web Shield.
It warned that 20121107.exe file from hxxp:/ /files.avast.com/files/emupdate is Win32: Evo-gen [Sups]. I think this is a mistake of the software.or so my computer has been infected with the virus (I run win 8 yesterday morning, and my friend gave me 1 usb which contain 1 folder. 1 video and 1 child virus Win32: Perkesh-D [RTK] names it is Systesm.exe. I think this virus can not infect your PC. because it does not have the autorun.inf file or autorun.ini., but I have to use USB Disk Security. so I think it can not be infected.'ve scanned many times. Hopefully Avast! explanation of the incident. Here’s a picture (Sorry I’m Vietnamese)

Anyone?

Already solved.

Milos