Thank you for the above described solution.
I did what you said and the error message is gone.
But to be honest it was a piece of hard work for a newbie like me. Because I am not quiet familiar with some of the terms it took me a while to follow what was meant.
I made a little protocol (in German only - sorry) of what I have done. Maybe this can be helpful for somebody.
Please follow: http://www.ahlers-web.de/blog/index.php ... ebaut.html
N.B.: As soon as I will have an English translation ready I will publish it here too.
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