you're not alone. It's a well known problem of many people with the NVIDIA Driver. I wait for one and a half year, that they manage it :-)
But it looks to give a solution. In a gentoo Forum they told to set the RenderAccel-Option in XF86Config off. I'm trying it right now and will see. It looks like working:
Option "RenderAccel" "off"
I hope it works more than the 10 min I try now ;-)
GeForce 2 MX 32 MB