UPDATE! Rated 5 out of 5 stars

Needs a new update (2012-08-16)
Thank you for your awesome downloader!

TY! it worked like a charm!

"Try clearing the cookies for youtube.com in your browser"

This review is for a previous version of the add-on (1.4.4.1-signed). 

Try clearing the cookies for youtube.com in your browser. If this doesn't fix your issues, send an email to deadline.support@gmail.com.