I've gone back to 8.35.5 for now as it actually does: detect my card as AGP, runs at 1680x1050 and doesn't have a memory leak .
and if that doesn't work then maybe it's better to stick with 8.35 if it works. i don't have agp so i cannot answer if they're supported in the right way or not.
I got mine to work, I had the PreInitDAL error initially aswell, but after using the other port, and lowering my gart in the bios from 512 to 256 it appears to work normally.
Hmm I also may have commented the "XAANoOffscreenPixmaps" option in my xorg.conf so it's back to the default (false i reccon). That's all i changed to get my X1950Pro AGP (512MB) to work (so far, wether it 'really' works remains to be seen as i haven't done much except 2d and glxgears
here's a few notes, at least with my install... FGLRX 8.44.3 does not have issues with memory leak, works in multiple monitors on opengl, although vlc will not render with opengl enabled and set to render on the second monitor.