I have the same issue, but on a different service provider (not youtube).
I have read all sorts of tech notes about headers being blocked in different flash player versions,
but the last I saw claimed that "Authorization" is allowed in player 10 (that I use).
But still, same error.
Have you found a solution ?
Make sure to check your auth string for hard or soft returns, and if it has
any, take them out. That solved it for me.
Yes, that did it.
Thanks a million !
Great, no problem.