I, too am seeing the illegal character bug. As with all such problems (see below), it started with a couple of videos, and is spreading like...well, that disease. Clearly some kind of service rollout. Hope the author can fix it.

To those who complain about it not working: there is a constant cat-and-mouse / whack-a-mole game between this plugin and the Tube. Youtube (purposely) breaks it, author fixes it. Wash, rinse and repeat.

So please cut the @feller some slack. However, *DO* report errors you are seeing. Try to be as clear as possible: the clearer it is, the sooner it will be fixed.