Hi lionfield,
I had the same error on my sbs2008 machine.
For me it turned out that the machine it was trying to communicate with was no longer around.
But it was still listed in the DNS server with an IP-adress. This adress was now assigned to a different machine. So when I tried to ping the machine name, the other machine was answering.
I deleted the DNS entry in the DNS server and flushed the DNS cache from a command prompt (ipconfig /flushdns)
In my search I also found this link about wireless clients:
http://forums.techarena.in/small-business-server/1253774.htmMaybe it helps you further.