Osx 10.5.2 on AMD :-)

[GMCivic]

First of all I Would Say Hello to everybody...

Tech Specs:
AMD x2 3200+
1GB Ram
Asus Mainboard (nForce Chipset)
Asus Grafic te5200 (nVidia)
21" Eizo Monitor

I Installed Osx on my System and everything works fine but i get 2 Errors after reebooting...

the first Error is a LaptopDisplay.kext error

and the second is a Problem with the Darwin Bootloader...
my System boots only from the DVD....but why???
I tried to set Guid boot options but nothing happend...

Any Ideas????

Sorry for my English... :-)