Hello Patrick,
I don't think I've seen the "fatal exception occurred" error before, but I know it has to be signed to work. Because it reads and writes files off of the local drive, Java won't let you run it unless it is signed. When I am making changes I normally leave the automatic signing option off in Netbeans so it compiles faster, but when I am going to put it online or use it elsewhere, I re-enable that option. Also, with JavaFX 1.3, I think you may have to be online to get it to work in any case so it can make sure JavaFX is up to date.
Let me know if you have any more questions (or if I failed to answer sufficiently),
Kyle