I played it to completion, in portable FireFox 31. Then, I downloaded it with 'Download Youtube Videos as MP4' extension, v. 1.7.
This is what I use for that task these days, replacing a couple other extensions that either ceased their own development, or did not remain compatible with the FF development. There appear to be versions of this for other browsers. (I'm slightly confused, in that I could have sworn I had this as a user script under Greasemonkey on one computer, but now it appears to be a regular, self-contained FF extension. No matter: it works.) There are also various external YT download tools, but a browser extension for this is usually more convenient.
Jordan
From: Carl Distefano
To: xywrite@xxxxxxxx
Sent: Monday, August 4, 2014 9:20 PM
Subject: Re: Workaround for DIR in VBox
I posted a short video showing U2 frame BDIR in action. You may (or
may not) be able to view it here:
http://youtu.be/7Qc05cMtt38I hedge because I myself am not able to view it under either Firefox
or IE. (It stalls with an error message a few seconds in.) However,
I can watch it on Chrome. Your mileage may vary.