If Firefox is indeed pointing you in the direction of the unresponsive script, then it looks like something you're pushing into an array. It's possible that that you're pushing a lot more data into the array than you intend. Or I could be completely wrong, as I am not what you would call a "power user" ; )
Unfortunately, you have a huge project with 2700 events. Personally, I test regularly so I can see if a new feature works or not, and I save many versions so that I can go back to a the most recent functional version in a case like this. Ideally, you would have been running the game and testing it as you developed, so you would have seen the moment where the game went from running correctly to running an unresponsive script. Of course that's not very helpful now.
Something you can do is start disabling blocks of your code to see if you can stop running the script that is causing the issue. Test and repeat until you find it.
Or you could ask for help again and publish the capx for others to look through.
There may be a more technical way to find what the problem is, but I don't know it.