Can you create a c:\temp directory, and set HKEY_LOCAL_MACHINE\Software\NPVR\LogNetPush=1 (DWORD), then do a recording, and zip and attach the c:\temp\netpush.txt file.
On a 64bit Windows machine, that registry setting will be HKEY_LOCAL_MACHINE\Software\Wow6432Node\NPVR\LogNetPush=1
I had the same problem when setting up my HDHR Prime. I had made all the firewall exceptions and even tested with the firewall disabled, no joy. Finally, I decided to power-cycle the HDHR Prime and shazam! It now records.
i3-3570k, 8GB RAM, Win10 Pro, Nvidia GT710, HDHomeRun (OTA), NPVR 6.x On a clear disk, you can seek forever...
I don't see "HKEY_LOCAL_MACHINE\Software\Wow6432Node\NPVR\LogNe tPush=1". I can go to the NPVR folder, but it only lists Default, DataDirectory, and InstallDirectory.