This can happen when you have a conflict with the added .cfg files and the possibilities in the controller. Unfortunalty, the error handling has room for improvements :grinning:. What kind of robot and external axes are you using?
RS does not have enough .cfg files to link all robots to all kinds of external axis (in the manual you will find a table of possibilities). If your configuration is not listed you will either have to use the system that is loaded into your real robot or ask someone at ABB to create the right cfg files.