I've just upgraded to XUbuntu 14.04. I installed Chroimum(chromium-browser package, not Google Chrome). Then installed by running:
sudo apt-get install pepperflashplugin-nonfree
sudo update-pepperflashplugin-nonfree --install
However if I try to load a flash element it still says it isn't installed and it doesn't appear under the chrome://plugins page either.
Running sudo update-pepperflashplugin-nonfree --status returns this:
Flash Player version installed on this system : 13.0.0.214
Flash Player version available on upstream site: 12.0.0.77