sorry for the incomplete change of the IP's, due to Sven making his last exams, I tried to fix the problem on my own, to not distract him.
That was the reason and I am sad that It didn't worked out well.
Administration is not my area. I can't prepare myself for everything, I am a busy guy, having to work and to care a lot of non administrative things on I-Mod, and when I got a message from our hoster, telling me that the old IP's get deleted, I checked, if all domains were set to the new IP.
I recognized they weren't and switched the other sites, !without! (Just now I know) rewriting the nameservers for the domains from the hoster's website-user panel, too.
Sry again,
Stefan