RGB-SCART, Metroid Prime and 60 Hz
 

Hi

I can't seem to run Metroid Prime in 60 Hz even though the manual says it should be possible provided I use a RGB-Scart and have a TV which support 60 Hz. I have both, but still when I switch to 60 Hz using the B-button during the "Nintendo"-logo all I get is an image that keeps "looping" downwards in a quick fashion. I've provided an image of my cable.

What could be the problem?

*edit*
I forgot to mention that this is a Gamecube and it's the PAL-version of Metroid Prime. Since the manual says the game is playable in 60 Hz I'm assuming it is (even though it's the PAL-version).