Can't get video on TV since 4.0 update

I have a 3GS updated to 4.0 and using Apple component cables. Since the 4.0
update I can't get a video to display on my TV just sound. A message appears
on the TV screen invalid format. The component cable inputs are 480i same as is the iPhone's NTSC setting which is also 480i. I have the wide screen on also.
Has anyone else experienced this problem? I have done a reset a reset to all settings and tried with the widescreen off, neither helped.