ati proprietary linux drivers

It seems the ATI proprietary linux drivers do not work on recent slack. I
tried them since slack 11.0 and never worked, even now on slack12.
I'm using everything by default with the smp kernel, the drivers always
result in an error while loading them at startx. probably i need to black
list some modules.
the eturned error is about this:
fatal error: load failed

my Gcard is an ATI radeon mobility X300


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