tks for the tip.
I also "deactivated" keylinks autodefined for all the query. The query opens at design time.

However the next problem (not solved so far is this).

query.open; - this is the line with error

the error
http://tinypic.com/r/2whkqa1/6

the query opens at design time so cannot be a SQL problem and also it has proper aliases.

SELECT C.*, CI.IDUSER
FROM CLIENTS C
LEFT JOIN CLIENTS_USERS CI ON CI.IDCLIENT = C.ID
WHERE C.ID IS NOT NULL
AND C.STATUS >= :STATUS
AND C.NUME LIKE '%%'
AND C.TYPEOF = 1
ORDER BY C.NUME
R