SAP Message REBDCA032 - You cannot make assignments between &1 and &2

Diagnosis
The assignment combination entered is invalid.
Only the following assignments are possible:
Relationship Type,,Source,,Target
Architecture -> Usage,,Arch. Object,,Business Entity
,,",,Land
,,",,Building
,,",,Rental Object
Usage -> Architecture,,Pooled Space,,Arch. Object
Extraction of Rental Space,,Pooled Space,,Rental Space