HD-A3 Movies Don't Play Video, but Menus are fine?

Hello,

I recently re-configured my HT setup, which is now:
- Panasonic 50" HDTV w/ 1 HDMI input
- PS3
- Toshiba HD-A3
- Comcast Cable box
- HDMI switch

Unfortunately my HD DVD A3 doesn't appear to be working properly. I popped in a disc and the loading menu appears fine. Once the video begins to play, unfortunately, the screen goes blank as if the signal is not being passed to the screen. The setup screens and all the normal menus play fine (which seems to indicate it's not a problem w/ either the TV or HD DVD player). I switched the HDMI cable on the HD DVD w/ the Cable box and still had the same problem, so I don't think its the cable.

Any ideas? This is baffling.

thanks

-simon