This is a known issue, please accept our apologies.
Temporary fix is described here(official forums sticky thread):
This should be fixed in near program update.
I've recently had an issue with AVG 9.0. Ever since I updated, it will periodically (Every 10-15 minutes) boot me out of any fullscreen applications I have up. I am positive it is AVG as a quick alt-tab to view open programs shows the AVG icon (it lasts only a short period of time), though nothing is 'open' on the desktop. I've gone through and disabled a deal of AVG automatic functions, but I've had no luck. Note: I don't know if this is occurring outside of fullscreen applications as there is no easily noticeable effect.
Windows XP Pro 32bit - SP2
2 gigs RAM
dual core AMD Athalon 64 X2 5000+ processor (2.6ghz)
Biostar MB (sorry, been a long time since I built my box, I don't recall the model)
I don't know the rest off-hand, but I can get them if necessary.
Program being run in full-screen: