Diagnosis
When you tried to find copy references for the necessary materialmaster segments, it is highly likely that not all the segments could becreated.

Procedure
1. Check the possible missing data using the "missing material mastersegments" function in the "Assortment" menu. A detailed confirmation ismade there.
2. Maintain the reference materials for each material group to such anextent that this error can no longer occur.
3. Alternatively, you can make another attempt to create the possiblemissing segments via the menu "Assortment - Mass maintenance - Generatemissing material master segments". The precondition for this, however,is that you provide suitable copy references for this purpose, byfirstly maintaining the reference materials per material group, forexample.