The problem is solved now. The problem was, that the path on the new server was exactly the same than on the old one, therefore I guess the php script was not able to start a new setup. I have moved the showkase folder to a subfolder, then I was able to run setup and after moving back to the original location running setup again solved the problem.

Thanks for your support

I have migraded my domain to a new Server, but now I get the message when logging in as "admin" in showkase:

Exception in file "admin classes auth. php", line 146
Message: User and password have not been changed: unable to store new user name and password

for backup, the old server is still running but the DNS entry is changed to the new server.

How to solve this problem?

Thanks in advance