I run FireFox 8.0.1 and 6.0.2 and have no problems as long as the builders did use proper html
It shouldn't matter if you try to load epm.exe as a page, The browser shouldn't crash (but it probably will, I haven't tried it). It may not display anything readable, but it shouldn't crash. Of course, no code is likely to be that bullet proof. On the other hand, if the content contains something that is trying to exploit a hole in the code (a virus), almost anything could happen, but a crash is the most likely result, unless you are running windows.
If you want to have the hard facts about a badly constructed web page, try this web site:
http://validator.w3.org/. It is also good to check, and fix, your own web pages, if you have any.
The best visited pages doesn't make use of flash or javascript. Why, because those pages is about the contents and not about the page itself.
Now this statement is true, but JavaScript does have a place when it comes to validating things like passwords. Of course, that should not be a complicated script, and it should be designed to run on any browser that supports JavaScript. Flash seems to be going away in that context, but it is still used for a lot of advertizing. FLASHBLOCK is pretty effective at reducing that sort of interference, but FLASHBLOCK itself stays running in the background, and that can cause intermittent crashes, just because it is not a good program (and that applies to all platforms, especially windows).
When I read the ff9 readme I was aware of that exceptq created reports (hadn't noticed that before), so I have sent them to the email address in the readme.
ExceptQ has been part of Firefox since about v4. If you follow the Mozilla news group, they say that you really should query such a problem there, before sending logs. I guess that they get so many that it becomes difficult to sort them out, and they hope to reduce the number by identifying duplicates, before they get sent. They also need detailed instructions on how to cause the problem.
None of that will really help with your problem though. FWIW, I am using FF 9.01, with no apparent problems, so I would suspect that some plugin might be causing the problem (unless it really is just a bad page, which you could avoid). I have FLASHBLOCK, and ADDBLOCK, installed. I also use the default theme, which may also make a difference.