(The magic file I was missing was libnss_dns.so.2)
If anyone is interested, here is a chroot jail version of Firefox 17.0.9:
Source can be found on slackbuilds or the mozilla site.
Quick instructions for use. Extract the firefox folder somewhere.
open a terminal
mount -o bind /dev /$PATH_TO/firefox/dev
The above step isn't entirely necessary for it to work, but without it Firefox will thrash your harddrive looking for something on every web page you visit.
Now this runs it as root which isn't the best idea. If anyone would like to come up with a script/instructions to run it as a separate user, that would be great.
Anyway, placing firefox in a chroot jail fixes my original problem.