WebCam+Avast=freeze

I’ve installed Avast (few days ago), and since then I see a problems with launching web-camera while Avast UI and SVC is running. Cam indicator lights up, but then whole system becomes non-responsive for few minutes (or until I disconnect cam). But as soon as I close both Avast processes this problem vanishes. Does anybody have some ideas?

WinXP SP3 (clean), two different web-cams with different drivers.

Thanks!