I had four folders in the connection list, being named
Zugang zu Kunden
Everything went fine but all connections in the first folder "Kundenzugänge" where empty. No server names, no user, etc.
After realising that the connections in the other three folders where imported correctly, I changed the name of the first folder to "Kundenzugang" on the source server. Import - Export - magically all connection details where there - except for three, which have vowels in there name :-)
It's not a big issue but I wanted to let you know and may be it helps others.