c:\temp does exist. If I disable live preview mode live TV does NOT work on the server. Note that the server has two hard drives, c: and e:. I have the live TV buffer set to e:\temp which does exist, and the video output directory set to e:\MyVideos.
When I tried live TV on the server with live preview mode disabled I got a black window. When I tried to close PVRX2 I could not. I opened the config utility to re-enable live preview and when I tried to close it I got a message to the effect that the program was recording and that if I continued I would lose what was being recorded.
I changed the live TV buffer to c:\temp and was then able to view live TV on the server with live preview disabled, however, I still could not get an image on the client.
SUCCESS! The problem is that the recording service EXE must be added to Windows Firewall as an exception on the server. Viewing live TV now works over both my 100 megabit network and my wireless 802.11g network.