That his narrowed it down nicely. In order to view the video, it must be saved in memory. If it played to completion, it would have restored that memory."Buffering..."
... I give up and stop the video and exit, and that's where the problem starts from....
Interrupting it left it in a condition that requires a battery pull to reset it.
That is something I have not experienced, but I do very little YouTube on my BlackBerry.