Thx for your help Bob. aviaServer was installed with Admin. rights.
I deleted Adm rights, but still it does not start with MSFS. (CD version)
I used FSuipc before with FSX. I suppose it is not necessary for MSFS PMDG.
So it is not activated anymore when starting-up MSFS.
I don't know which ini file I can use for the link with aviaServer.