Diagnosis
You have maintained a plant and MRP area in the pool, even though youhave not flagged the force element as "stockholding".
Flag the force element as stockholding, or delete the plant and MRParea in the pool.
You must delete MRP areas using transaction./ISDFPS/BERID_DELE. When doing so, ensure that the force element towhich the MRP area is assigned is not being processed in processingmode in the Structures workbench.