I have been fighting the problem with flash 9 crashing firefox on flash sites such as YouTube for quite a while now with no success. I have Ubuntu Fiesty installed with flash 9 installed with apt.
I have deleted the two entries in my plug-in file so that the non-free plug-ins would be used, I have checked my about
lug-in file and there is nothing out of place there. I have also added, "export XLIB_SKIP_ARGB_VISUALS=1" to my firefoxrc file as well as my /usr/bin/firefox file. I have checked for extension compatibility, tried everything I could in the Ubuntu forums, MozillaZine forums plus numerous other places that Google led me to. Also my xorg is set at 24 bit.
Additionally, I have looked at other distro forums and the problem with Flash 9 and FireFox 2+ is prevalent for those users as well and not distro specific. I also ran FireFox from the terminal but did not get an error msg when it crashed.
I am not by any means a computer expert and just can not find anything else to try. If someone has a different trick up their sleeve, please, please, pass it along?