I just sent my Ceton 4 back for the memory problem several people on this forum had also experienced. In the meantime I bought an HDHR Prime, set it up, swapped the card, re-paired same card (via chat w/Cablevision, took 10 minutes). So far all is good, 20 minutes from out of the box to passing the "Tune HBO tests".
During the initial set up I had a little glitch, I received a UPnP error. I have two DLink DIR 655 'routers'. The downstairs router is set up as a router, DHCP, UPnP, multicast etc. The upstairs is set up as a WAP/wired switch... UPnP off, no DHCP (however multicast is and I believe has been on). This set up has worked fine for the 5 years I've been using it... rare re-boot, but, essentially works just fine. When I was setting up the HDHR, I turned UPnP on on the 'WAP' router and the setup worked fine. The TV was on here and there throughout the day/evening, no problems... or, so I thought, turns out recordings were dropping after a few minutes (5-15).
Troubleshooting the problem has revealed this: What ever state UPnP is in on the WAP, when the 'No Tuner Available' error message shows up, I change the status (check or uncheck) and reboot the 'WAP router' and whatever signals I'm consuming (1-3) come back in seconds. However, they are short lived and recording can't work unless I let the recording start, drop with the tuner, switch the UPnP state, reboot the router and manually restart a single recording. Within minutes of the tuner status changing (second tuner on, channel change etc.) the No Tuner Available error message appears... swapping the UPnP status on the WAP router and a re-boot brings it right back.
Again, this set up worked for 5 years until I added the HDHR to the network. I am not using the WAN port on the WAP router (192.168.0.2), DHCP is off on the WAP and set to a range of 0.100-199 on the actual router, which has UPnP on, and multicast streaming is on on both routers. The HTPC is hardwired into the WAP router, as is the HDHR. The WAP is hard wired to the router.
It is very strange that changing the UPnP status and rebooting temporarily resolves the issue, regardless of the UPnP state (yeah or nay). Multicast streaming is enabled on both devices... ....
Just happened now while I'm typing this, no tuner status change, just all of a sudden, Viewing or Listening Conflict, No tuner available to satisfy the current request... Turning UPnP on (from a state of off) gave a 'Files needed are not installed.... Restarting WMC and boom, CNN HD shows right back up.
Hard wiring the SD HDHR directly to the routher (DHCP server) isn't so easy as I don't have Co-Ax easily there. I can't imagine I'm the first person to have this problem, but, I can't find anything conclusive on the SD site/forums or in the HDHR Prime forum on green button.
This is driving me crazy, and WAF will plummet prior to the Ceton coming back home... Any help is greatly appreciated.