list_fields not working on query

[eluser]toopay[/eluser]

Code:

$query = $this->db->get($mytablename);
$list1 = $query->list_fields();
echo 'this is the first call on table results: <br />';
print_r($list1);
echo '<br />this is the second call on table results: <br />';
print_r($list1);
$query = $this->db->get('tad_keywords');
$list2 = $query->list_fields($mytablename);
echo '<br />this is the first call on full table: <br />';
print_r($this->db->list_fields($list2));
echo '<br />this is the second call on full table: <br />';
print_r($query->list_fields($list2));