I seem to remember those cards having problems with desktop affects back in the old driver days when using the default 24-bit color depth.
Can you edit your /etc/X11/xorg.conf, and force it to 16-bits instead? This might be the tradeoff to get it to work if 16-bit color depth is usable for you.
Ie, something like this:
Code:Section "Screen" Identifier "Screen0" Device "Card0" Monitor "Monitor0" DefaultDepth 16 SubSection "Display" Viewport 0 0 Depth 16 Modes "1024x768" EndSubSection EndSection