After extreme hardware problems on the server machine everything is back up and running again.
Both hard disks crashed so we had to restore the backup from January, 9th 2013, which was about two days old. Sorry about this, but the backup from January, 10th was compomised with most likely corrupt data because of the dying hard disks.
Our server provider Hetzner keeps telling us that hard disks are expendable items and that it is completly normal that there are hard disk crashs. Well, 5 disks in 6 months, we do not believe this. Also because we are running root servers for almost 10 years and had 1 or 2 failing disks until we got this machine here…
Guys, sorry again!