I would recomend to install SP5 and try again.

>Getting the following error using Web Browser 04.01.0015 in a VFP6 form:
> Fatal error: Exception code=C0000005
>
>The error is intermittent, but seems to be happening more frequently for some users. It may have started when we went to Windows XP, but no guarantee on that.
>
>I have already tried adjusting the Sys(2333) settings to no avail.