[GESIOR2012]Problem with redeem a coupon system.

[Croow]

Hello, I found that redeem a coupon system:
https://otland.net/threads/gesior2012-redeem-a-coupon-system.236850/
...and im trying to enter it on my server, but I got that error when trying to enter page where I can change a code for PP..

Parse error: syntax error, unexpected '[' in C:\xampp\htdocs\pages\redeem.php on line 15

line 15 of redeem.php:

$result = $query->fetchAll(PDO::FETCH_ASSOC)[0];

full code of redeem.php:

<?php
if(!defined('INITIALIZED'))
    exit;
if($logged){
  if(isset($_POST['code'])) {

    $code =  $SQL->quote($_POST['code']);
    $query = $SQL->query('SELECT * FROM `__cornex_redeem` WHERE `code` = '.$code.' LIMIT 1;');



    // Key exist in database
    if ($query->rowCount() >= 1) {
      // $query = $query[0];
      $result = $query->fetchAll(PDO::FETCH_ASSOC)[0];

      if ($result['used_by'] > 0) {
        $error[] = 'Key has already been used';
      }

      if (!empty($error)) {

        foreach ($error as $err) {
          echo $err.'<br>';
        }

      }


      if (empty($error)) {
        $time = time();
        $code = $result['code'];
        $points = $result['points'];
        $querys = sprintf('UPDATE `__cornex_redeem` SET `time`='.time().', `used_by`='.$account_logged->getId().' WHERE `code`="'.$result['code'].'" ');
        $SQL->query($querys);
        $account_logged->setPremiumPoints($account_logged->getPremiumPoints() + $points);
        $account_logged->save();

        echo 'Amount of '.$points.' points has been added to your account!';
      }

    } else {
      echo 'Key is not valid';
    }

  }
$accid = $account_logged->getID();
$main_content .= '
<form action="" method="POST">

    <input type="text" name="code">
    <input type="submit" value="Redeem">

</form>';
} else {
    $main_content .= '
<div class="ui warning message">
  <div class="header">
    You dont have permission to do that!
  </div>
</div>
    ';
}

Thanks in Advance for help.

Im using Gesior2012.