Trigger

Can someone please help me in writing trigger for the below :

TRIG_STED_AIU trigger on table STATE_TAX_EXEMPT_DEFAULT
after insert or update of columns STED_RES_TAX_EXEMPT_PCN, STED_IND_COMM_TAX_EXEMPT_PCN do the following:

Update all BUSPART
Set BUS_RES_TAX = 100 - STED_RES_TAX_EXEMPT_PCN
BUS_IND_COMM_TAX= 100 - STED_IND_COMM_TAX_EXEMPT_PCN
where buspart_state = sted_state_cd
and (If sted_item_type_id = 1 and BUSPART.util_type_code = ‘G’ (gas)
or
sted_item_type_id = 2 and BUSPART.util_type_code = ‘E’ (electric) )
and buspart_reltyp ‘LD’ (utility)

Note: there may be no existing business partners to update, so do not create an error in this circumstance.

 

Wrote the following :

CREATE OR REPLACE TRIGGER RSSC.TRIG_STED_AIU

AFTER INSERT OR UPDATE OF sted_res_tax_exempt_pcn,sted_ind_comm_tax_exempt_pcn
ON RSSC.STATE_TAX_EXEMPT_DEFAULT
--REFERENCING NEW AS New OLD AS Old
FOR EACH ROW
WHEN (BUSPART.buspart_state = STATE_TAX_EXEMPT_DEFAULT.sted_state_cd
AND
(STATE_TAX_EXEMPT_DEFAULT.sted_item_type_id = 1 AND BUSPART.utl_type_code = 'G'
OR
STATE_TAX_EXEMPT_DEFAULT.sted_item_type_id = 2 AND BUSPART.utl_type_code = 'E')
AND
BUSPART.buspart_reltyp = 'LD')

BEGIN

UPDATE ALL BUSPART
SET BUSPART.bus_res_tax = 100 - STATE_TAX_EXEMPT_DEFAULT.sted_res_tax_exempt_pcn,
SET BUSPART.bus_ind_comm_tax = 100 - STATE_TAX_EXEMPT_DEFAULT.sted_ind_comm_tax_exempt_pcn

END TRIG_STED_AIU;

Getting the following error :
ORA-04076: invalid NEW or OLD specification

 

Can someone please help me