Hi Carsten,
The "Save Changes" doesn't work?! That's troubling.
I have no idea what's going wrong. To help me isolate the problem can you:
1.) Give me an exact example of a change you're trying to make, e.g. changing the birth date from March 23, 1863 to March 24, 1863, on Ter_Horst-23 -- something that specific.
2.) Tell me what sort of operating system and browser you're using, e.g. Windows XP with IE 9 or whatever.
Thanks!
Chris