Wow - that's bizarre....
But, hey, I'm not going to question it! :) Just take it and mutter a quick thank you to the computer gods and go about my business!
Honestly speaking, experimenting with different browsers' online install was way down on my list of things to try from the beginning.
And, the fact that other versions installed with no problem really threw me for a loop.-- I still doubt it's a Firefox "issue" - otherwise there'd be a lot of other documented instances. Could be something on your compy interacting with Firefox in a weird way...... But, there I go questioning the computer gods. I'll shut up now :)
PP
Oh I don't think it's a Firefox issue either PP. Honestly...think it "may" all go back to that Elluminate and how it is interacting with "whatever" in some way. It of course requires Java to operate and looking at their help site there are several things I see...
One being exactly what you did, try different browsers and if it works in a different browser then use only that browser.
If you have problems on one computer that is in a network then try exactly the same steps on a different computer in the same network, if you can replicate the problem on that computer then the problem is with the network, not the computer and not Java.
You must also configure the Firewall to Elluminate program AND Java Web Start, …