PS2 won't work when I have it hooked into the A/V port on my widescreen tv.

[SPIDER-MAN-ROX]

I can't see the video when I have my PS2 hooked directly into the A/V port on my widescreen tv but I can hear the audio fine. When I run my PS2 through the A/V port on my VCR/DVD player that I have hooked into the same A/V port on my widescreen tv then I am able to see the video & hear the audio just fine so why isn't it able to work when I hook my PS2 directly into my widescreen tv?