Running pulseaudio -k then pulseaudio -d should restart pulseaudio and temporarily fix your issue. For a more complete fix that doesn't stop working, I had to download the latest flash and install manually. This should work for you on firefox - other browsers may need the libflashplayer.so placed elsewhere. Google should help if that is the case.

(directions taken from here)

Open http://get.adobe.com/flashplayer/otherversions/

Choose Linux 32-bit on Step 1

Choose Flash Player 11.2 (tar.gz) on Step 2, download the file

Once download is complete, right click on the file (tar.gz) and click on Extract here

Launch Terminal (Keyboard Shortcut : Ctrl+Alt+T)

Go to that location where you extracted the file

Run this command : sudo mv libflashplayer.so /usr/lib/firefox-addons/plugins

Launch Mozilla Firefox and check do you have Adobe Flash Player