The URLs do work in my browser, i.e. I get to the point where I can click on the RSS symbol with 'View XML'.
Then, if I do that, the MM-vodcast subscription box opens, with the URL pasted (including 'format=xml') and the error message: Unknown Protocol.
In iTunes I didn't use Jeugdjournaal podcast yet but I did use EenVandaag, without any problem.
And also: the three other vodcasts (Journaal 7 + 20 + Nieuwsuur) have no problems. Before I THOUGHT they had, but that wasn't true. it was a matter of settings: only 1 download at a time possible.
As to Dutch vodcasts: apart from what NOS News and EenVandaag offer I don't know any. Did check out a few other current affair programs, they do offer streaming video but often capturing/downloading/vodcasting not possible - often for copyright reasons, that is what I am told.
The best sites for streaming video are www.uitzendinggemist.nl
(public tv) and www.rtl.nl/xl/#/gemist/
They offer the option to view 'missed broadcasts' online.
Is my assumption correct that you are of Dutch background? Your fast find of EenVandaag and Jeugdjournaal suggests it - and so does your nickname The Flying Lowlander...