The latest "stable" versions is 18.104.22.168. Is that what you have?
Does it fail with any other browsers, Chrome for example?
You might try going into your System Preferences, Flash Player, selecting the Advanced tab, and delete all browser data and settings.
There's also a Storage tape in the preference pane that includes an option to delete all local storage settings by site. You might also consider that or doing it selectively (by site).