I have all the latest versions of Firefox and the plugins...yet I have experienced this problem with the last several versions of FF - every 2 days or so the Flash Plug-in gets set to 'Disabled'.
To correct this I simply go in and re-enable it and the browser works fine again for several days.
I have done all the updates, the Flash update is the latest etc.
You appear to be running Firefox 16. The latest version is 18.0.1.
You appear to have Flash Player 11.4.402.### installed. The latest version is 11.5.502.146.