Like Joergen said, it seems to be a problem with x360 VGA unable to view PAL interlaced modes right. All games that require old Live! updates give this wronly formulated message about wrong video modes. It should say "does not work with VGA cable".
It's the same thing with few BC games. Forza and Simpsons Hit and Run give the same error and refuse to run with VGA. I've checked the VGA retail box and it doesn't say anything about the incompatibility problems. I also checked the BC list page and it doesn't say anything about it either. I've wasted my money on a few Xbox games I've bought because they don't work when they shoud.
I've called the x360 help line and explained the situation. They've had calls about the problem but can't do anything about it. They said I should address the problem straight to MS, who got my letter and addressed it back to x360 helpline. Who will probably address it back to MS.
It's good to know that my investment doesn't work like it should and that my complaintment letter is being volley-balled around. I'm pretty sure someone will phone me from the helpline and give me once again the wrong advice that my cable is broken and that I need to replace it.

I got the problem solved..
The games i tried works fine now.. i dont think the poroblem is the display setting..
But a flaw in the Xbox 360.
A simple solution to the problem is, as mentioned before, just to temperarely use a composite, or component cable, update your Xbox game, and afterwards, use the VGA cable again.
Halo 2 works very fine now,. Just played it on live last night..
Thanks for all the help...