I was on your site this afternoon as a non member and I notice that you turn off the hovering ad script and now you turn it back on.
While I was on the site this afternoon, my browser didn't crash. Right now, I'm on your site as a member and my browser didn't crash either.
I feel this Mozilla bug that is related to one fo your script is not giving any clues to you why it's happening.
Last night my browser crash 3 times and none it was near the ads meaning my cursor was not near the ads.
But for the login which you used the hovering feature on it, when I click on login and was about to type my username and then it crashes.
I know that you are pretty frustrated that this bug doesn't give you any leverages (meaning giving you some clues where it is started). This bug is pretty tricky.
Honestly, I know you been asking members to do this and do that and want this bug to crash their browser immediately. I don't want you get upset but asking member if their browser are crashing after you do changes so you can see if the problem is this and that is pretty far-fetched. It seems to me you want some magic potion and cast a spell on Mozilla to see where to pin point the issue.
I'll be honest with you, I do want this issue to be resolve too because it's not good to read something on your site then my browser crashes.
So I hope you are closed to solving the issue, but so far my browser hasn't crash, so something you been doing is working.
So hang in there