Well, I have to say, I think I talked too soon.
It seems the router does not like mixed signals.
When I first tested it was just a wireless N laptop with a wired desktop.
Last night, I was working on my old wireless G laptop, while trying (and I do mean try) to transfer a 700MB file from laptop to desktop and from desktop to laptop. I just could not do it. "Network source/destination not found".
The wireless G laptop and the desktop were in the same room. The wireless N laptop was in another room (20 feet away).
This morning, with the wireless G laptop shut down, and just the wireless N and desktop running, both in the same room, I had no problems transferring the same 700MB file. Go figure.
I'll try some more things and let you know.