SQL & PL/SQL

Hi
I've created the following 2 tables

create table cruise_orders
(cruise_order_id number,
order_date date,
constraint pk_co primary key (cruise_order_id, order_date));

create table order_returns (
order_return_id number,
cruise_order_id number,
cruise_order_date date,
constraint pk_or primary key (order_return_id),
constraint fk_or_co foreign key
( cruise_order_id,cruise_order_date )
 references cruise_orders (cruise_order_id , order_date))

And i inserted 2 records into cruise_orders table

insert into cruise_orders values(1,sysdate) 
insert into cruise_orders values(2,sysdate) 

SQL> select *from cruise_orders;

CRUISE_ORDER_ID ORDER_DAT
--------------- ---------
              1 27-JUL-11
              2 27-JUL-11

And i tried to insert the records into order_returns table
But getting the parent key not found error.. though the record exists in the parent table

SQL> insert into order_returns values(1,1,sysdate);
insert into order_returns values(1,1,sysdate)
*
ERROR at line 1:
ORA-02291: integrity constraint (SCOTT.FK_OR_CO) violated - parent key not
found

Guide me where i'm doing mistake.

Thanks