Comment 2 for bug 86377

more than likely its not flash issue. Im leaning towards this being a totem plugin issue more so than flash as it has been seen alot in feisty. see bug #86265.
Without the backtrace we can not tell what the problem is.
Michael Feisty uses Flash9 by default.
Leslie
Can you please follow the instructions at: https://wiki.ubuntu.com/MozillaTeam/Bugs
to generate a backtrace using the firefox-dbg package.