In Foglight Experience Monitor (FxM), The service steps were edited. None of the service step names were modified. When the service is saved the message: "A Service Step already exists appears with the same name as one of the Service Steps below". That is not true; none of our other Services use any of these Service Step names.
Product Defect. This issue is being tracked as FXM-143. Duplicate service steps (when there are no duplicates in fact) are getting added to the configuration database.
rename _all_ of the Service Steps in that Service to be something you had not previously used.
Issue fixed in version 5.6.2. the latest version of FxM can be downloaded here.