You have to go to the video you want to upload first. Then hit the BlackBerry button and scroll to Send > Upload to YouTube. Once there, at the very top on the right, you should see your username. If not, it probably says Log In or something, Click it, type your information in, but then make sure that "Stay Signed In" is UNCHECKED. You have to make sure you do that in this window, not in the YouTube app. It's not even the same thing. Hope I helped!