trying to add a line item (non-serialized item) in a script on an invoice and its giving me this error

currRec.setSublistValue({
                             sublistId: 'item',
                             fieldId: 'item',
                             value: 7211,
                             line: Number(lineCount),
                             ignoreFieldChange: false,
                             forceSyncSourcing: true,
                         })
                       
                        currRec.setSublistValue({
                             sublistId: 'item',
                             fieldId: 'location',
                             value: 1,
                             line: Number(lineCount),
                             ignoreFieldChange: false,
                             forceSyncSourcing: true,
                         })

                        
                         
                         currRec.setSublistValue({
                             sublistId: 'item',
                             fieldId: 'quantity',
                             value: quantity,
                             line: Number(lineCount),
                             ignoreFieldChange: false,
                             forceSyncSourcing: true,
                         })

                            currRec.setSublistValue({
                             sublistId: 'item',
                             fieldId: 'rate',
                             value: 0,
                             line: Number(lineCount),
                             ignoreFieldChange: false,
                             forceSyncSourcing: true,
                         })
                         log.debug('Free Shipping', 'triggered2');
                         currRec.setSublistValue({
                             sublistId: 'item',
                             fieldId: 'amount',
                             value: 0,
                             line: Number(lineCount) ,
                             ignoreFieldChange: false,
                             forceSyncSourcing: true,
                         })