make sure you have proper file permissions for your kernels, but also... make sure you have the right system.kext file with each associated file.

boot with -s
/sbin/mount -uw /
chmod -R 644 /[name of your kernel] && chown -R root:wheel /[name of your kernel]
chmod -R 755 /System/Library/Extensions/ && chown -R root:wheel /System/Library/Extensions/
rm -R /System/Library/Extensions.mkext
reboot

also, read up on the voodoo kernel (like Rogue said)... I've had a lot of luck with this one myself and the future looks really bright for the newer developments to come.

EDIT: the link to the post for the patcher app is: http://www.infinitemac.com/f36/amd-p...ta-test-t1375/
This shows it being hosted off rapidshare.

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