So once more its working so far....
Can you explain me the following...
The only problem was that I have to give the IP instead of localhost for the db-server at installation.

localhost is declared at /etc/hosts, so don't understand why there's a prob...
hm, who cares It's working for now

you mean ip 127.0.0.1 ? or real IP ?

I had to give the real IP ( 192.168.40.102 )
sorry for the late answer...

maybe your mysql only binds to the external ip...