Error when run the SQL query

Anyone know the root cause of the error? Thanks.

"Error[07001][Oracle][ODBC][Ora]ORA-01008: not all variables bound"

I am connecting the oracle DB and run the SQL query with the parameters

SELECT ES.CNTR_NUM, ES.FCIL_CDE, ES.CLASS_SIGNATURE, to_char(ES.EVENT_CRE_DT, 'yyyy-mm-dd hh24:mi:ss')
, to_char(ES.EVENT_DT_LOC, 'yyyy-mm-dd hh24:mi:ss'), to_char(ES.EVENT_DT_GMT, 'yyyy-mm-dd hh24:mi:ss')
, ES.DOC_REF, ES.SHIPMENT_NUM, ES.PROCESS_STATUS, to_char(ES.UPDATE_DT_GMT, 'yyyy-mm-dd hh24:mi:ss')
FROM EQM_EQP_STAGING ES
WHERE ES.CREATE_DT_GMT > to_date('20130501', 'yyyymmdd')
and ES.CNTR_NUM IN (:eqp_num);

wailun3