Comment 60 for bug 239182

From: http://blogs.adobe.com/penguin.swf/2008/08/windowless_mode_fix.html

"As a reminder, Firefox 3.0.1 has a known crash problem with a wide variety of windowless mode SWFs. This has already been fixed in the Mozilla code tree and alpha builds are available for download. However, if you would prefer to wait until a new official Firefox release, you may wish to disable windowless mode in the Flash Player. You can do this (on any platform) by setting WindowlessDisable=true in the mms.cfg (which lives in /etc/adobe on Unix platforms)."

I have uploaded a deb for the latest release candidate for Flash to my PPA that disables windowless mode via this method (the way it's done is a little hacky, but it works). I can confirm it stops these crashes entirely.

https://launchpad.net/~psyke83/+archive

Disabling wmode is highly recommended at the moment because a) we need to wait for Firefox 3.0.2 and b) 64bit users will need the latest development release (>=1.1.0) of nspluginwrapper that supports windowless mode, which isn't available in the repositories yet.