Hi Eric, you were saying that you get a number of those:
AAVM - scanning error: ClientRqDispatchThread: OpenEventsAndMapping failed - client probably died, 00000159.
in the Event Log. Each such an error should be preceded by another one (a different message, such as "OpenEventsAndMapping: xxxx failed"). Do you see any such a message? If so, can you post their exact form?
Or even better, can you post the contents of the file <avast>\data\log\error.log?
BTW aren't you, by any chance, using the Fast User Switching feature of Windows XP? Or a Remote Desktop?
Thanks
Vlk