All three of those videos are working in cuteTube on my device. It sounds like your ISP is doing something that modifies the YouTube server response. It could be due to some traffic-shaping activities.
Can you download the web page for one of those videos and send it to me via email (address is in the 'About' dialog in cuteTube)?
cuteTube actually dumps the response when there is an error, but I think the qDebug output is suppressed in Harmattan for release builds. You can try by launching cuteTube from the terminal: Code: /opt/cutetube/bin/cutetube
/opt/cutetube/bin/cutetube