Problem changing digital channels

[Mark_H]

So now that I have mapped the QAM channels on my HDHomeRun, I have run into a new problem. I can tune to any of the mapped digital channels, but if I go back to the TV Guide and then select any other digital channels I get an error message telling me there is no usable signal on that channel. If I exit the UI and relaunch it I can select any digital channel but again cannot change channels without getting the same error message.

[Mark_H]

I have found that when changing channels with the channel up/down buttons it seems to work correctly. If I go to the guide and select a different channel, or back out to the menu and then select Live TV, I get the No Signal message. This problem does also seem to impact the analog channels.

My Configuration:
Asus M3N78-VM Motherboard
AMD 2.3 GHz Phenom Triple Core CPU
4Gb RAM
1Tb SATA Drive
HVR-2250 (configured as analog only at this time)
HDHomeRun (both tuners configured and mapped)
HVR-1600 (drivers loaded but not configured in GB-PVR at this time)
Windows XP Pro with SP2