Now I have some time to investigate. I have loaded a copy of the databse on another disk. I booted from a CD and activated the profile. Upon reboot the same issue came up again. The problem seems to be that it cannot find files mounted under the /usr.
On my running ZS I notice that /usr is symbolic link on /cdrom/usr. My suspicion is that something is wrong either with fstab or with /dev/ram2 with acts as root of ZS.
Anyone any idea?