DVBViewer client works fine on Media server pc with tv card but on a remote client on the same lan I got 'No Hardware Available' error.
I spent ages trying to get this to work.
I solved it as follows
Make sure RTSP is enabled on the server.
On the client go to hardware and in devices on the right side delete any that are there then select add, then select RTSP network device. Enter the ip address of the server and the ports exactly as the RTSP settings on the server. Close and reopen the client and it worked for me. The only issue I had then was that I got sound but a black screen. I resolved this by going to settings and selecting Video output B. All ok now.