In Firefox (Menubar) go to 'Tools > Add-ons > Plugins > Check to see if your plugins are up to date', like suggested in the screenshot.
This will open up a new tab, looking like this:

Now you know, that your Shockwave Flash-plugin is (most likely) out of date!
To fix this i suggest, that you first install Ubuntu restricted extras
from within Software Center (if you haven't already done so). Make sure to tick the box Adobe Flash plugin
. You can also mark the others too! Or install via shell:
sudo apt-get install ubuntu-restricted-extras
I checked Adobe FLash Player Help HP and v. 11.2.202.310 is the latest available/supported so far. I guess there is not much you can do right now, but wait for a new release!
Quote: 3. Find the latest Flash Player version available for your operating system:
Linux:
Mozilla, Firefox, SeaMonkey (Flash Player 11.2 is the last supported Flash Player version for Linux. Adobe will continue to provide security updates.) 11.2.202.310
