I had the same problem, I installed WinTVcap and it now works if I select winTVcap as recorder plugin, but when I select live tv a recording is done at the channel i'm watching.
If I select Direct recording plugin I get the same error:
"Failed to communicate with GB-PVR RecordingService.....".
I'v use the modified installer because the normal didn't install the files in "program files" but in "programmer", but I had the same error in the normal installer.
I have tried both direct and wintvcap, and receive the same error message in the gbpvr.exe.log file about the socket exception. Also I do not have a GBPVRRecordingService.exe.log in my windows/system32 directory. Perhaps my recording service is not even getting started?
Take a lookin the control panel->administration->Services. It should be listed there as GB-PVR Recording Service. It should be listed as "started".
I'm not sure why its not there. You could try manually installing it.
From a command prompt, change into the C:\Program Files\devnz\GBPVR directory. Run "installutil GBPVRRecordingService.exe". Then reboot.
Installutil may not be in you path. It'll be in a directory like C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322, so you may need to stick that path in front of the installutil command.