I registered for the sole purpose of thinking Darrell for his suggestion. :-)
We had some issues early on with the Vista CDs our supplier supplied. Turns out we received non-Volume License CDs when we should have had Volume License CDs.
I had completely forgotten about this trouble until Darrell suggested that the particular error in question could be tied to non-VL media. That's exactly what's going on with one of our machines It will not accept the server as a viable KMS server. Now we know it's because it was hand-loaded with a single user copy of Vista.
We'll have to Wash-n-Wax the machine to fix
the problem, but that's OK...we'll just do it next time it comes in for service.
Thanks much, Darrell!