Comment 78 for bug 81858

The XaaNoOffscreenPixmaps option also worked for me, and also fixed a similar problem with a bit of experimental javascript as seen on this page:

http://www.raizlabs.com/blog/?p=210

Perhaps this can help narrow down the problem.

Note: ubuntu 7.04, firefox 2.0.0.6, video is nv17 (geforce4 440 go) according to "Device Manager" using nv driver (nvidia's doesn't work for me).