Message SAP WV191 - The net/net PP found is negative

Diagnosis
The net net purchase price that was determined during pricedetermination is negative.

System Response
A sales price cannot be calculated for this item.

Procedure
Check the basic purchase price and all the conditions that are used todetermine the net net purchase price. In particular, pay attention tothe absolute conditions with a negative sign. If necessary, set thesecondition records to "not relevant to pricing".