How is your HD PVR connected to the STB? Your log shows that you are using YRYBY. Are the audio cable connected to the connectors on the back of the device?
I use composite on the front. That seems to be the only difference between your device and mine. If TME works, then connection is not the problem.
While the video is playing, right click, go to "DirectShow filters" menu, and click "Hauppauge HD PVR Crossbar". On the resulting property page window, select "Audio Decoder Out" from the "Output" combo box on the right-hand side. Make sure the Input combo box shows "Audio Line In". If not, change it and click Apply. See attached screen shot.