Originally Posted by Hoth
Opera and Flash haven't played well togeather for a year or two. I've read that Opera 9.50 finally fixes the problem... not sure if that includes the currently available beta.
I downloaded Opera 9.50b and the newest flash but it's still really a no go. It works sometimes, but when I play YouTube videos the whole thing freezes and I have to kill it, or wait a while and see the grey box again. Some people reported success though: http://ubuntuforums.org/archive/index.php/t-694567.html
In my opinion you're better off with Firefox if you want to use flash.