Change date format in options date and time from "jS F Y" to "d.m.y" and it works in english. But unfortunately not in german.
Try to change language and got an error:
The value of locale "de_DE" could not be found on the server.
Could be related to Serversoftware. So I will try to figure it ou by myself.
e.g. (from admincp)
US-Format (z.B., 04-25-98): m-d-y
Erweitertes US-Format (z.B., April 25th, 1998): F jS, Y
Europäisches Format (z.B., 25-04-98): d-m-y
Erweitertes Europäisches Format (z.B., 25. April 1998): jS F Y