SAP Message REBDCA018 - Higher-level objects of &1 are already assigned in another hierarchy

Diagnosis
A usage object, which is superordinate to the current usage object, isalready assigned to a different architectural hierarchy. The subordinateobject, however, has to be assigned to the same architectural hierarchyas its superordinate object.

System Response
It is not possible to assign the current usage object to the selectedarchitectural hierarchy.

Procedure
Select an architectural object from the same hierarchy to which thesuperordinate usage object is assigned.