I just tried it on Ubuntu 13.10 with firefox. This is the Mint 16 Mate 64 distro. No dice. I get an
Icedtea Web (Open JDK, which is an open source implementation of the java web browser plugin) error. The error is a java runtime error. This is a brand new distro, so I expect the java stuff is up to date, but I haven't looked explicitly. Its more likely that Icedtea is missing something that the tractrac app is trying to use. The error is a java runtime error of some sort (NetxPanel.RunLoader). This comes after the security popup where I say its ok to run this app.
Just to add, I'm also running 10.8.5 on a MacBook Pro and have no problems with tractrac in firefox. As I recall the upgrade from 10.6 fixed lots of things.