302 error after ajax request. How to fix?

Question

PHP

Actually, the request itself:

function delCompares() {
    ShowLoading("");
    $.get(dle_root + "engine/ajax/compare.php", { compare_id: '1', action:'delete', skin:dle_skin}, function(b) {
        HideLoading("");
        if ( b != 'ok' ) {
          DLEalert(b, dle_info);
        } else {
          alert('Ошибка');
        }
    });
    return false;
}

And the php handler:

} elseif( $_REQUEST['action'] == "delete" ) {
    $db->query( "UPDATE " . USERPREFIX . "_users SET compare='' WHERE user_id = '{$member_id['user_id']}'" );
    $buffer = "ok";
} else {
    die( "error" );
}

The response is a 302 error. Why and how to fix I have no idea what could be the problem?