I am running WinXP, NIS 20011 and PowerDesk 6 on a Dell 9100.
I posted an item about this topic two months ago when I had installed NIS 2011(trial) on a single computer (Dell 4300). I was able to get the problem resolved. It was a bandaid but the loss in functioinality was so small that it really did not matter.
I eventually purchased NIS 2011 and recently installed in on a 2nd computer (Dell 9100). No surpirze, I ran into a similar problem with PowerDesk and with Windows Explorer. The error messages were different but I assumed that the fundamental problem was the same. So I tried the fix from Avanquest (see original thread) and it worked. Strangely, that same patch did not work with the first computer (both are running identical copies of WinXP, PowerDesk and NIS).
The purpose of this 2nd thread is just to let others know that the patch from Avanquest may solve their problem. I would have added this to the original thread but it seems to be closed to new content.