SAP Message AC081 - Percentage rate specification missing.

Diagnosis
You have chosen a changeover method which requires you to specify a netbook value percentage rate. Changeover to the changeover calculationkey is carried out when the declining balance of the asset falls belowthe net book value percentage rate (relation of the net book value tothe acquisition value).
If no percentage rate is specified, then the changeover takes place atbook value 0.

Procedure
Check your entries.