urgent - need to solve this error: "unknown software exception (0xc0000005)"

[zange]

Hi there,
When I am running vizard (3.0) there sometimes occurs an error message saying:

"The exception unknown software exception (0xc0000005) occurred in the application at location 0x69cce734.

Click on OK to terminate the program
Click on CANCEL to debug the program"

I'm running an experiment at the moment and it's really annoying when this happens since I lose all the data. Any help would be very much appreciated,
thanks