Very very thankful to your quick response.

The problem is that neither the program(Avast) nor any of its component(from its parent folder) is running. Avast taskbar icon too is not being displayed on account of those registry hacks . I thought its resident scanner is tuned off, b'coz I also didn't found any avast process in the process manager of HJT(taskmanager is disabled!). But, combofix warns me of the avast scanner being running.

To turn on the main program(Avast), I first used MABM to remove those registry hacks and restarted(PC) to find the avast main program running. I rightclicked and disabled every protection but still the same problem with combofix!

I think the only solution will be to uninstall avast. Am I correct?