Передача параметров в FastReport из c#

Пытаюсь передать цифры в стринговом формате в фаст репорт в sql запрос. Но выдаёт ошибку:

Ошибка построения отчета: ORA-01861: литерал не соответствует формату строки

c#:

report.SetParameterValue("ClientOrderN", txbClientOrderNumber.Text);
report.SetParameterValue("ClientOrderI", txbClientOrderItem.Text)

часть sql запроса в fastreport: (l.ORDER_NUMBER = (:ClientOrderNumber||'-'||:ClientOrederItem) or (:ClientOrderNumber is null and :ClientOrederItem is null) ORDER_NUMBER типа varchar, параметры в fastreport типа variant. Кто знает в чём причина моей ошибки подскажите пожалуйста. Не как не могу разобраться.

select PIPE_NUMBER, PIPE_YEAR, WC_INSTANCE, WORKCENTER_ID, RETURN_REASON, DIAMETER, THICKNESS, MELT_NUMBER, PART_WELD, STEELMARK, VENDER, WAREHOUSE_BEFORE_MOVING, res_und_order, CREATE_DATE, INSERT_OPERATOR, Date_Cancel_With_Reserved, Operator_PRM,
case when  Date_Cancel_With_Reserved is not null and res_und_order = ORDER_NUMBER and RETURN_ADDRESS is null then 'Подтверждено'
when Date_Cancel_With_Reserved is not null and res_und_order <> ORDER_NUMBER and RETURN_ADDRESS is null then 'Не подтверждено'
else 'Активно' end as reserv_status
from(
select p.RETURN_ADDRESS, p.ORDER_NUMBER, m.PIPE_NUMBER, m.PIPE_YEAR, s.WC_INSTANCE, r.WORKCENTER_ID, s.RETURN_REASON, m.DIAMETER, m.THICKNESS, m.MELT_NUMBER, m.PART_WELD, m.STEELMARK, m.VENDER, s.WAREHOUSE_BEFORE_MOVING, s.ORDER_NUM_RES||'-'|| s.ORDER_ITEM_RES as res_und_order, s.CREATE_DATE, s.INSERT_OPERATOR, first_value(p.CREATE_DATE) over(partition by m.SHOP_ID, m.PIPE_YEAR, m.PIPE_NUMBER order by s.CREATE_DATE desc, p.CREATE_DATE nulls first) as Date_Cancel_With_Reserved, row_number() over(partition by m.SHOP_ID, m.PIPE_YEAR, m.PIPE_NUMBER order by p.CREATE_DATE) as RN, first_value(p.INSERT_OPERATOR) over(partition by m.SHOP_ID, m.PIPE_YEAR, m.PIPE_NUMBER order by s.CREATE_DATE desc, p.CREATE_DATE nulls first) as Operator_PRM from WC_MAIN m
left join WC_7_3_SGP s on m.SHOP_ID = s.SHOP_ID and m.PIPE_YEAR = s.PIPE_YEAR and m.PIPE_NUMBER = s.PIPE_NUMBER
left join WC_4_8_PRIEMKA p on m.SHOP_ID = p.SHOP_ID and m.PIPE_YEAR = p.PIPE_YEAR and m.PIPE_NUMBER = p.PIPE_NUMBER and p.EDIT_STATE = 0 and p.CREATE_DATE > s.CREATE_DATE
left join WC_1_2_LIST l on m.SHOP_ID = l.SHOP_ID and m.PIPE_YEAR = l.PIPE_YEAR and m.PIPE_NUMBER = l.PIPE_NUMBER
left join ROUTE_PIPE_MOVES r on m.SHOP_ID = r.SHOP_ID and m.PIPE_YEAR = r.PIPE_YEAR and m.PIPE_NUMBER = r.PIPE_NUMBER
where s.RETURN_ADDRESS is not null and s.ORDER_NUM_RES is null and s.ORDER_ITEM_RES is null and m.EDIT_STATE = 0 and s.EDIT_STATE = 0 and l.EDIT_STATE = 0 and r.ACTION_DATE = (select max(ACTION_DATE) from ROUTE_PIPE_MOVES where PIPE_NUMBER = m.PIPE_NUMBER) and s.WC_INSTANCE = (select max(s.WC_INSTANCE) from WC_7_3_SGP s where s.PIPE_NUMBER = m.PIPE_NUMBER) and s.CREATE_DATE BETWEEN to_date(:START_DATE) and to_date(:END_DATE)
and (l.ORDER_NUMBER = (:ClientOrderNumber||'-'||:ClientOrederItem) or (:ClientOrderNumber is null and :ClientOrederItem is null)))
where RN = 1 and
(PIPE_NUMBER >= :PipeStart or :PipeStart is null)and
(PIPE_NUMBER <= :PipeEnd or :PipeEnd is null)and
(Date_Cancel_With_Reserved like to_date(:DateCancelReserv) or to_date(:DateCancelReserv) is null);