I have the same issue of this topic: "Added video URL shows undefinedundefined... and does not display video"
But i have the error only on IE 9.
You can check the site here: www.lorenzettipipe.com
I have all the permission on the files and folders, and the plug-in is correctly configured i think, since on other browsers (even ie7-8) the video works.
What can i do to fix the issue?

Same issue, visible here:
test.petitestetes.com/joomla/jeux-educatifs-en-ligne/histoires-racontees/histoire-le-petit-chaperon-rouge.html

Is there a fix for this ?

Julien