Here is developer's response for the update:
about further releases, after I upload a new release it takes about 2 weeks for AMO to check it and make it public. If everything goes well, it will take me 3-4 weeks for new release +2 weeks for AMO, so 5-6 weeks for new release to go public.
Nevertheless, I must admit, I have a lot of problems with new Flash Player 10. As you've probably noticed, YouPlayer works fine with Flash 9, but doesn't work with Flash 10. This is because some security changes were made, and it prevents YouPlayer to play videos and control the player. I've been trying to make it work for 2 weeks now, with no success, and I'm starting to run out of ideas. Unless I make it work, making a new release is pointless. I'll keep you updated on how it is going, and I hope it will be good news.
Such message is better to be put in the addon description so that everyone knows what's going on and there may be someone has idea on how to solve the problem.
Otherwise, the comment page will soon be flooded with 1-star reviews... :/