>Yep. Looked at that, and didn't find anything that seemed to apply. The thing that has me puzzled is that the program works OK as long as the files are being hosted on just about any other machine except the domain controller. When hosted on the domain controller I'm getting the C0000005 error, and it seems to be on forms that use the COMDLG32.OCX control (forms that don't use the control seem to work OK).
>Only other factor I can think of (that I forgot to mention previously) is perhaps it might have something to do with a VPN connection (which I presume is the case, as the server is not in the same location as the workstation). We've had customers with VPN connections before, though never had this sort of problem (though we did experience issues regarding speed due to limited bandwith).

Someone had recently had a longish thread here about various versions of commdlg32 (now was it TerryT or JimN or...) and the trouble one of them was causing. Now if it's only the OCX, you may need just to copy and register one from a machine which works, but if it's deeper, somewhere in the dlls to which this ocx is a wrapper, then... it may be quite hard to replace, because you'd not only need to reboot, you'd need to schedule it to be replaced during a reboot. Last time I had to do something like that it was a NT4 workstation, which at least had good console mode where I knew my way around. Nowadays, I'm not sure I'd know.

Of course, if the ocx is to blame at all.