Diagnosis
You are using plan versions in manual planning to which differentplanning hierarchy versions have been assigned.
You can only plan or compare plan versions within a planning session ifthey use the same planning hierarchy version.
The planning hierarchy defined the frame for all the characteristiccombinations that are still to be planned. Within a planning session, apart quantity of this characteristic combination is being processed.
Different versions of the planning hierarchy can contain completelydifferent characteristic combinations and they cannot therefore be usedtogether in a planning session.

Procedure
Only use plan versions that have been assigned the same planninghierarchy version.