jQuery Grid Plugin - jqGrid

Hi, j created a database and unfortunately i can't visualize it. As I noticed the problem is linked to the "id" value - in fact if I change the id value of the table it doesnt work (as I have many tables in my database I have to make a differance between each id). please help

My code that doesn't work with id_car from the car table:

while($row = mysql_fetch_array($result, MYSQL_ASSOC)) {

$response->rows[$i]['id']   = $row['id_car];

$response->rows[$i]['cell'] = array($row['id_car'],$row['name_cart']);

$i++;