Host variable in subqueries

Hello
We've got a question regarding the using of the host variables inside
subquery in declaration of cursor. Is there any restriction about it? We
had
problem in the following cursor:

EXEC SQL DECLARE ACQ CURSOR FOR
SELECT Id FROM
(SELECT SKey,CheckIn,CheckOut
FROM Stayed
WHERE Id= :given_id ) TheMan, Stayed
WHERE TheMan.SKey=Stayed.SKey AND TheMan.CheckIn=Stayed.CheckIn AND
TheMan.CheckOut=Stayed.CheckOut;

When we change :given_id to 9675467 (its real value) it works properly.
Do you have any idea what the problem is?

Thanks in advance.
Alexander & Yuri