mysql error when adding function

The following error is returned when trying to use a MySQL function..

#1418 - This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its
declaration and binary logging is enabled (you *might* want to use the less safe 
log_bin_trust_function_creators variable) 

I couple of days ago I started using replication..? Don't know if this could have an incluence on it?! But I know one thing - it has worked :)

If I try to override (add the function again) the same error occurs..

The function

DELIMITER $$

DROP FUNCTION IF EXISTS `stock_in_stock_ids` $$
CREATE DEFINER=`dynaccount`@`localhost` FUNCTION `stock_in_stock_ids`(_running_total_limit INT, _product_id INT, _group_id INT) RETURNS TEXT
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE _running_count INT default 0;
    DECLARE _id INT;
    DECLARE _count INT;
    DECLARE _ids TEXT DEFAULT NULL;

    DECLARE _cur CURSOR FOR SELECT id, count FROM stock WHERE group_id=_group_id && type=2 && product_id=_product_id ORDER BY time DESC, id DESC;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN _cur;

    read_loop: LOOP
        FETCH _cur INTO _id, _count;

        IF done THEN
            SET _ids = '0';
            LEAVE read_loop;
        END IF;

        SET _running_count = _running_count + _count;
        SET _ids = CONCAT_WS(',', _ids, _id);

        IF _running_count >= _running_total_limit THEN
            LEAVE read_loop;
        END IF;
    END LOOP read_loop;

    CLOSE _cur;

    RETURN _ids;
END $$

DELIMITER ;