MediathekView is a fine application, but for me, sometimes it fails to stream some shows. Fortunately, you can right-click any show and inquire its streaming URL.
On Ubuntu,
rtmpdump then fills the gap for me, for example:
rtmpdump -r 'rtmpt://foo/bla/fasel/foo.mp4' -o foo.mp4
Revision: r1.1 - 11 Oct 2012 - 16:07 - ClausBrod