A noticable difference is that the following line shows for the Wii & PS3 but does not appear in the DCERouter.log when I select the PVR:
05 03/02/10 14:45:00.086 Media_Plugin::StartMedia() function call completed with honors! <0x86fdcb90>
So... It appears that something might be failing when I select PVR which then causes an MD 'on' command to be sent... no orbiter and no PSS because the rest of the system thinks the PVR is showing (no stop media command has been sent).
I'm hoping someone has an insight into this... anyone?