My version of Flash Player:
11.6.602.168
I'll try to go back to 10.3 tonight and I'll let you know 
Concerning Chrome, there are websites that have the YouTube videos embedded. I can't even see the video. The area where it should be remains empty. On YouTube itself everything works perfectly. The problem is with embedded videos on some websites (on some it works, on others it doesn't, weird :S), and with watching YT videos on Facebook.
Thanks for the hint though, I'll try with 10.3