dual head output problem

I have a dual head video card radeon 700. I am hooking to both my lcd and a new plasma tv(using component connections.)

some .rm file played perfect on both lcd and plasma tv, but some others can be played using RealOne without a glitch on lcd, but when I drag to the plasma screen, there is no video output: you can hear the sound, you can saw the realone frame but the video part is totally black.

I think it’s the codec problem, can anybody help me to solve this problem? thanks a lot.