Maybe the "DIAL Communication Service" is deactivated on your computer system. This service is responsible for the exchange of data between different processes e.g. catalogs, documentation and so on. DIALux will not function correctly, if this service is deactivated or uninstalled.
Therefore you should open the control panel -> computer management -> services and search for "DIAL Communication Service" make a right mouse click on it and select settings. As a starting type there should be “manual” selected. Then you should restart the service.