I doubt that you tried *all* YouTube usernames, and you failed to give me *one* specific example (that's all I asked!), and so I can't reproduce your bug here, and so I can't help you. Use 2.11 and it will work. If not, the YouTube feature is not meant for you. Feel free to use cuteTube or something else. Sorry!
Where there's a will there's a way-N900 RoCK!!