It is a problem with a dial up connection... even with broadband some videos on youtube can take ages to load at busy times. You could try pausing it, then leaving it for a while to load ( there is usually a bar that shows how far it's loaded, wait until it's reached the end before playing) - meanwhile use a separate window to continue to surf the net whilst you wait.
By the way, I've changed the link now - it's not on youtube anymore but a different site. Emma couldn't watch the first link but got it with the new link, so maybe give it another try.