Indeed, FGLRX on the specific 2.6.32 version of the Linux kernel is blacklisted for possibly security-sensitive crashes. This is https://bugzilla.mozilla.org/show_bug.cgi?id=724640 . As the drivers are closed source, it's very hard for us to assess how security-critical this kind of driver crash is, so we have to be slightly paranoid.
That being, said, to stop the FGLRX-bashing below: the most recent versions of the FGLRX drivers (since a few months) on very recent Linux kernels work very well (pass almost all WebGL conformance tests, no crashes anymore).