First thank you guys for the suggestion. Here is my set up:

DVD----Component vido----AV reciever
----coaxial audio---- AV reciever
HD reciever---DVI/HDMI---AV reciever
---optical----AV reciever-----HDMI-----Plasma TV.
I could not find a setting in the menual special for digital -out like Alan mentioned. And it should have nothing to do with my HDMI connection when i watch OTA HDs, it is built-in tuner for the plasma TV....It might be the copy right protection.

Thank you guys again,

Han