I added routerip="mybackendip"; below the line already there and reran the script. Sorry that didn't fix your problem, you may want to look at, /var/log/pluto/*MythTV_Player.log on the MD and see if it helps with why the frontend is dying/restarting. With my networkcontrolport problem I had lots of:
Going to send command jump livetv
Connect() failed, Error Code 111 (Connection refused))
messages. I would get live tv for about 30 seconds then the player (being unable to connect to the frontend) would kill the process and restart the frontend.