Hi,
Bad news ahead:
This site is embedding videos from "netu.tv".
We used to have a working plugin for that video hosting site a long time ago but then they introduced
heavy anti-downloader measures.
See related forum threads e.g.
here.
If you're lucky you will find other tools on the Internet (e.g. github.com) that can handle this.
If you don't find anything, you can still use a screen recording software as a last resort.
-psp-
EDIT
Afaik they made sure that all common tools and methods to download videos fail, also
this method.