Problem with audio on select channels (1 Viewer)

I'm having a strange problem with audio on my satellite system. I lose sound on just two channels and only some of the time. Basically, on two of the channels I have audio during the programs, but not during the commercials, which is not that bad, except that sometimes it is just the opposite, where I hear the commercials and not the programs. If a program or commercial starts with audio, then I will hear the whole program or commercial. In other words, the audio doesn't cut out during the commercial or program. I have a pioneer VSX-D608 receiver and the DirectTV HR23-700 HD DVR PLUS. I am using the optical audio out on the DVR to my receiver for audio and an HDMI cable to the TV for video. I also tried the digital audio coax output from the satellite box to my receiver for audio with the same results.The thing that really puzzles me is that all of the other channels are fine with no audio problems at all. Another interesting thing is that I just switched from DISH network and was having the exact same problem (same channels even). Any ideas or advice would be greatly appreciated.

Connect the analog stereo outputs (red & white RCA connections) of the satellite receiver to your HK receiver.

Do they have the same dropouts?
If not, then your receiver is having problems re-syncing when the digital audio source changes at the originating station.

Exactly which channels are having the problems?
If it is at the source, other people should hear the same problems.

I do have sound through other connections. If I turn the TV speakers on, the sound is there through the HDMI cable, but I want to get surround sound with HD channels through the receiver, which, unfortunately doesn't have any HDMI inputs. My TV doesn't have any of the audio outputs that I need either. The channels are NBC and CBS (channels 2 and 6 respectively in central FL). Thanks for the reply.