Diagnosis
To set up a hierarchy of external components, you must specify thecomponent levels. You also have to descend the structure one level at atime, otherwise the system cannot create the hierarchy correctly.
You have entered two neighboring rows and, although the structure in thehierarchy is descending (lower row > upper row), there is more than onelevel between them.

System Response
The system cannot set up the hierarchy and the operation is canceled.

Procedure
Correct your entries.