db2 query problem

[eluser]Unknown[/eluser]
I use the db2u driver provided on http://codeigniter.com/wiki/DB2_Database_Driver/

In my controller I have a basic index function:

Code:

function index()
{
    $data['query'] = $this->db->query('SELECT * FROM CITIES');
    $this->load->view('start_view', $data);
}

This query works when I use the "Control Center" tool, but gives me an error when used in codeigniter:

Code:

A Database Error Occurred

Error Number:

SELECT * FROM CITIES

the same thing happens when I use other similar queries...

Code:

$this->db->query('INSERT INTO cities (cityid,cityname) VALUES ("201","Arcadia");');
$this->db->query('SELECT * FROM ADMINISTRATOR."CITIES"');

apache access.log gives ma an error:

Code:

127.0.0.1 - - [04/May/2010:19:33:42 +0200] "GET /29.04.2010-final/codeigniter/ HTTP/1.1" 500 553

Did you maybe encountered a similar problem or might guess what I'm doing wrong?