SAP Message /SAPPCE/PNV017 - Cost element &1 must have negative value, since cost element category &2

Diagnosis Cost element &V1& has a positive value. However, as this cost element isfrom cost element category &v2&, you must transfer a negative value. The SAP System requires a negative input value, so it can make apositive posting on the debit-side. Procedure Transfer a negative amount for cost element &V1&.