cavshell.dll one function work, other not :/

I have installed Comodo Internet Security x64, everything was good, but next i found out that the context menu item “Scan with Comodo” not works(it does nothing, clicking it just disable the context menu, i mean nothing runs or something like than). but other context menu item “Run in Sandbox” work properly, why is this?’
i’m Using Windows 7 SP1 x64.
P.S. MD5 Hash of cavshell.dll is D4C2C1C9180F88F35067481438BCF501

REINSTALL fixes this.