Thank you ptsenter, I think I worded my post very poorly. What I meant to ask (and what the tech was answering) was which file types the Nero server could handle, not whether Nero was the only server that would work. He was telling me that Nero could only stream MPEG's. Sorry for the confusion. But you are right, he is not correct in any case, because even the manual seems to indicate that the Nero should be able to stream more than just MPEGs.
However, I think I am going to go the route you are, and try alternate server software, like Tversity or Windows Home Server and see what happens. If it still will not play, then I will know it is the unit that has the problem.