I had buy this webcam with his software in a reputable retail store .
I have resolved the problem so :

  1. Install the software without Avast ;
  2. Open the interface of Avast ;
  3. Clic on setup in up right position ;
  4. Clic on global esclution ;
  5. Write : C:\Programms\Vimicro\VmicroUSBPCCamera(VC0342)\vmcam\bin* ;
    And now is all OK .
    Many thanks to all for help . By .