Flash tends to crash browsers in Ubuntu very often. I have a fix for that.
I tried it and I couldn't get Firefox to crash.

Go to terminal and execute this whole big command:

Code:
wget http://launchpadlibrarian.net/13470096/nspluginwrapper_0.9.91.5-2ubuntu2_i386.deb && sudo dpkg -i nspluginwrapper_0.9.91.5-2ubuntu2_i386.deb && sudo apt-get remove --purge flashplugin-nonfree && sudo apt-get install flashplugin-nonfree libflashsupport