Вопрос по информатике:

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(); }?>