Нужна помощь в исправлении синтаксической ошибки? Вам сюда!

<?php
    include 'head.php';
    ?>
<div id="main">
    <div class="post"><div class="post_top">
        <div class="post_title"><h2><a></a><a><font color='red' bold="bold">Авторизация пользователя</font></a></h2>
        </div></div>                
        <div class="post_body"><table width="100%" cellpadding="0" cellspacing="0"><tbody><tr>
            
            
            <?php
                if(isset($_POST['id']) and isset($_POST['auth']))
                    {
                    $auth = mysql_escape_string(trim($_POST['auth']));
                $id = ntval($_POST['id']);
                
                $req = mysql_query("SELECT * FROM `users` WHERE `vk_id`='" . $id . "' LIMIT 1");
                if (mysql_num_rows($req))
                {
                    $user = mysql_fetch_assoc($req);
                    if($auth == $req['auth'])
                    $_SESSION['vkid']=$id;
                    $_SESSION['auth']=$auth;
                    echo "<center>Вы успешно авторизовались</center>";
                }else{
                    $nick = 'id' . $id;
                    
                    $log = getpage('/prison/universal.php?method=getInfo&user='.$id.'&key='.$auth);
                    $begin = '<result>';
                    $end = '</result>';
                    $enter = pars($log,$begin,$end);
                    if($enter=="0")
                    {
                        echo "<center><font color='red' bold>Неверный ID и AUTH KEY</font></center>";
                    }else{
                        mysql_query("INSERT INTO `users` SET
                            `vk_id` = '" . $id . "',
                            `nick` = '" . $nick . "',
                            `auth_key` = '" . $auth . "'
                            ");
                        echo "<center><font color='green' bold>Вы успешно зарегистрировались</font></center>";
                    }
                    if($_GET['action']=='exit') {
                        unset($_SESSION['id']);
                        unset($_SESSION['auth']);
                        session_destroy();
                        echo "<script text='javascript'>location.href='/';</script>";
                    }
                    
                    
                    if(!$_SESSION['vkid']) {
                        echo '
                            <form action="" method="POST">
                            
                            <table width="100%" cellpadding="0" cellspacing="0">
                            <tbody>
                            <br>
                            <tr>
                            Ваш ID:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;
                            <input type="text" class="inputadd" name="vkid" value="" placeholder="Ваш ID"><br><br>
                            </tr>
                            <tr>
                            
                            
                            Ваш auth_key:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;
                            &nbsp;
                            <input type="text" class="inputadd" name="authkey" value="" placeholder="Ваш auth_key"><a href="/chat.php">(?)</a><br><br>
                            </tr>
                            </tbody></table>
                            
                            <tr>
                            
                            
                            
                            </tr>
                            <br>
                            
                            <div>
                            
                            <center><input type="image" src="index_files/okay0000.png"/></center>
                            
                            </form>
                            ';
                    } else {
                        include 'edit.php';
                    }
                    ?>
            </td></td></td></td>
            
            </tr></tbody></table>
            <div class="post_metadata"><div class="content">
                <center>
                    
                    
                </center>
                <div class="post_metadata"></div></div>
            </div></div></div>
    
    
    <?php
        include 'foot.php';
        ?>