Error - 'cannot insert duplicate key row in object 'dbo.MRPASSEMBLY' with unique index By_Parent' or 'cannot insert duplicate key row in object 'dbo.MRPASSEMBLY' with unique index By_Parent'

Error was found when processing SQL statement. SQLSERVER\FMAST: cannot insert duplicate key row in object 'dbo.MRPSTOCKDETAIL' with unique index By_Stock_Type. the duplicate key value is (1,MA,Q221 , , ,0,0,0,0). The following could not be processed.