What type of video? Puntuado con 2 de 5 estrellas

I tried this extension on the Youtube and Google Video sites, with not results. Did I not turn on a setting?

Esta valoración es de una versión anterior del complemento (2.4.5). 

Re: What type of video?

You might read the manual (http://www.downloadhelper.net/manual.php) then eventually ask support (http://www.downloadhelper.net/support.php) if you still have troubles.