I have the Galaxy 10.1 and have become quite annoyed at the You Tube experience... I get a lot of messages than the video is not available on mobile... I only have a wi-fi equipped unit.
My app is working fine as well, but I tend to use my tablet a lot like I use my laptop, so I'm just in the browser most of the time anyway. I view youtube in the browser like on a regular computer and everything is the same.
Thanks... the app works fine. It just won't allow all content to be played as it sees this device as a mobile device... Viewing YouTube in a browser solves the issue... I'm sure your 3 yr old has this all figured out...