H21/200 Dolby Digital has dropped out on receiver, no more 5.1 audio on new Samsung TV&Digital Home Theatre

Hi,

This is the second HD satellite receiver in our home the other is the HD/DVR. Have a new 46 Samsung TV D630 and a Samsung Home Theatre HT-C555. About two weeks ago I noticed we no longer had surround sound effect when watching HD tv stations. I have called tech support and a ticket has been generated for the engineers but I was interested if anyone else has had this happen to them.

Settings on the HD Satellite Receiver-Audio-Dolby Digital is set on

I feed HDMI from sat rec to HDMI on TV, I then feed audio via optical audio out on sat rec to in optical audio on the Home theatre receiver.

I use to hear all 6 speakers when on HD programming now I am only getting front-l/r,center and subwoofer.

I checked the TV settings and the Home theatre audio settings and they are reading PCM under audio settings, there is another box to check off Dolby Digital but I can not highlight it anymore. The DVD player within the Home Theatre receiver is able to put out 5.1 Dolby Digital fine. I tried moving my HD/DVR to this location and when I connected the one feed for Directv the screen prompted me to check the cabling, I assume looking for the 2nd feed for the DVR? The HD/DVR has generates a digital signal for a different set up and I get surround sound at that location. The cable for this situation is new, new HD receiver, new TV and new Home theatre.

So even though the satellite receiver says it is putting out Dolby Digital signal my TV and my Home theatre receiver sees it as PCM. Any ideas? or should I bug DirecTV for a new receiver?