Различные вопросы по PHP и MySQL

<?php
define('_IN_JOHNCMS', 1);
include "incfiles/core.php";
 
$last_id =$id;
 
$text = isset($_POST['text']) ? functions::checkin($_POST['text']) : '';
 if (empty($text)) {
    $error[] = 'Введите текст сообщения!';
} elseif (mb_strlen($text) < 10) {
    $error[] = 'Слишком короткий текст!';
}

if (!empty($error)) {
    $ref = functions::checkin($_SERVER['HTTP_REFERER']) ;
    echo functions::display_error($error, '<a href="'. $ref .'">Назад</a>');
} else {

mysql_query("INSERT INTO `cms_news_comments` SET
`refid` = '$last_id',
`time` = '" . time() . "',
`user_id` = '" . $user_id . "',
`text` = '" . mysql_real_escape_string($text) . "';");
 
$_SESSION['error'] = '<div class="gmenu">' . $lng_news['added_message'] . '</div>';

}

<?php

/**
 * @package     JohnCMS
 * @link        http://johncms.com
 * @copyright   Copyright (C) 2008-2011 JohnCMS Community
 * @license     LICENSE.txt (see attached file)
 * @version     VERSION.txt (see attached file)
 * @author      http://johncms.com/about
 */

defined('_IN_JOHNCMS') or die('Error: restricted access');
error_Reporting(E_ALL & ~E_NOTICE);
ini_set('session.use_trans_sid', '0');
ini_set('arg_separator.output', '&amp;');
ini_set('display_errors', 'On');
date_default_timezone_set('UTC');
mb_internal_encoding('UTF-8');

// Корневая папка
define('ROOTPATH', dirname(dirname(__FILE__)) . DIRECTORY_SEPARATOR);

<?php

define('_IN_JOHNCMS', 1);
include 'incfiles/core.php';

$error = []; #<---Объявление массива НЕ удалять!
$last_id = $id;
$text = isset($_POST['text']) ? functions::checkin($_POST['text']) : '';

if (empty($text)) {
    $error[] = 'Введите текст сообщения!';
} elseif (mb_strlen($text) < 10) {
    $error[] = 'Слишком короткий текст!';
}
 
if (!empty($error)) {
    $ref = functions::checkin($_SERVER['HTTP_REFERER']) ;
    echo functions::display_error($error, '<a href="'. $ref .'">Назад</a>');
} else {
    $sql = "
        INSERT INTO `cms_news_comments` 
        SET
            `refid` = '$last_id',
            `time` = '" . time() . "',
            `user_id` = '" . $user_id . "',
            `text` = '" . mysql_real_escape_string($text) . "'
    ";
    
    mysql_query($sql) or die (mysql_error());
     
    $_SESSION['error'] = '<div class="gmenu">'. $lng_news['added_message'] .'</div>';
}