After installing the newest version of Flash Player, on most YouTube videos I try to play the message, "An error occurred. Please try again later." comes up. Also, on websites like Tumblr other media, like audio and videos uploaded there, don't play at all - it's just a blank white space where it should be. This all works fine in Chrome. I've tried everything I can think of - I cleared the cache and removed cookies, updated all plug-ins, uninstalled and reinstalled both Flash and Firefox, disabled Ad-Block, ran it in Safe Mode and private browsing, restarted my laptop a couple of times - but none of it worked.