Hi,
I think you're better off getting advice from a place like hometheaterforum.com, but I'll take a stab at this:
1. I would guess it's just sharing the setting with the regular surround channels. Are you sure you enabled the surround back properly?
2. Logic 7 only runs on a stereo signal through the 525, so that probably means your DVD was playing a stereo track by default. The 525 does let you save default processing modes per input, but I don't know if it stores proccessing modes for both stereo AND surround contingencies on the same input. You probably want to just find the 5.1 channel track on the disc, if it has one.
3. This probably indicates the # of channels in the source material. DPLII and Logic7, in that case, would both show just two speakers. Very few DVDs have DTS ES or DD EX with the sixth channel in there; in those cases, though, you should see the indicator light appear.
-Cooper
