помогите исправить ошибку:

<?php    $mysqli = false; function connectDB() {  global $mysqli;  $mysqli = new mysqli("localhost", "root", "", "mysite-local");  $mysqli->query("SET NAMES 'utf8'");    } function getAllArticles() {  global $mysqli;  connectDB();  $result_set = $mysqli->query("SELECT * FROM `articles`");  closeDB();  return resultSetToArray($result_set); } function getALLGuestBookComments() {  global $mysqli;  connectDB();  $result_set = $mysqli->query("SELECT * FROM `guestbook`");  closeDB();  return resultSetToArray($result_set); } function addGuestBookComment($name, $comment) { global $mysqli; connectDB(); $success = $mysiqli->query("INSERT INTO `guestbook` (`name`, `comment`) VALUES ('$name', '$comment')"); closeDB(); return $success; } function getArticle($id) {  global $mysqli;  connectDB();  $result_set = $mysqli->query("SELECT * FROM `articles` WHERE `id`='$id'");  closeDB();  return $result_set->fetch_assoc(); } function resultSetToArray($result_set) {  $array = array();  while (($row = $result_set->fetch_assoc()) != false)     $array[] = $row;  return $array; } function closeDB() {  global $mysqli;  $mysqli->close(); }?>