Due to the fact that all domain users have a directory-redirection of (the folder) application data to a network location, Nokia PC Suite was not able to write the configuration data to this network directory. Though the user had all necessary rights to do this, it seems to be a problem of the software dealing with network ressources.
Copying the configuration files (Folder 'Nokia', 'PC Suite' from application data) from a local user installation to the application data folder on the network ressource solves the problem.