trouble on trigger

I have a trigger, when I'm running the update query it's fine but when i'm put into trigger it's error

CREATE OR REPLACE TRIGGER EXCHG_RATE
AFTER UPDATE ON CURRENCY
FOR EACH ROW
BEGIN
  UPDATE PRICE
  SET SELL_PRICE =
    CASE WHEN EXTRA_COST_CURRENCY = 'IDR' THEN       ROUND(((25* COST_PRICE) + EXTRA_COST_PRICE) *
(1+(MARGIN_PERCENTAGE/100)),-3)

    ELSE
      ROUND(((25* COST_PRICE) + (25* EXTRA_COST_PRICE)) *
(1+(MARGIN_PERCENTAGE/100)),-3)

    END
  WHERE COST_PRICE_CURRENCY = 'USD';
END;
/

Please help me find the error...

Thanks,
Setiawan Wijaya Received on Thu Dec 14 2000 - 04:52:22 CST