format code appars twice error

I get format code appears twice error in the following query

SELECT SCHEMEDETAIL.DISCOUNTAMOUNT,
       SCHEMEDETAIL.DISCOUNTPERCENT,
       SCHEME.SCHEME_ID
  FROM SCHEME, SCHEMEDETAIL
 WHERE     (SCHEME.SCHEME_ID = SCHEMEDETAIL.SCHEME_ID)
       AND (SCHEME.FLAG = 0)
       AND (SCHEMEDETAIL.FLAG = 0)
       AND SYSDATE BETWEEN TO_DATE (EFFECTIVEDATEFROM, 'DD/MM/YYYY HH:MM')
                       AND  TO_DATE (EFFECTIVEDATETO, 'DD/MM/YYYY HH:MM');