Hello,
I had contact with the german support.
First I tried a downbgrade, installed the file (ftp://ftp.dlink.de/dns/dns-320l/driver_software/DNS-320L_sw_language_package_de_fr_103_20150427.zip), did the update but nothing changed.
*cry* But after one or twe hours, thy brought the anwser:
In the webIF, on top, on the right, you can change the lan language by klickin on the globe.
It was so simple, ... too simple for someone like me *bangonthewall*
Thanks for all :-)
Yours Frank