Fatal error: Cannot instantiate non-existent class: simplexmlelement
<p>I'm using this php script</p>

<pre><code>$error = false;
if(isset($_POST['login'])){
    $username = preg_replace('/[^A-Za-z]/', '', $_POST['username']);
    $password = md5($_POST['password']);
    if(file_exists('users/' .$username . '.xml')){
     $xml = new SimpleXMLElement('users/' .$username . '.xml', 0, true);
     if($password == $xml-&gt;password){
      session_start();
      $_SESSION['username'] = $username;
      header('Location: agis-employees.html');
      die;
     }
    }
    $error = true;
}
</code></pre>

<p>And I end up with this error</p>

<blockquote>
  <p>Fatal error: Cannot instantiate
  non-existent class: simplexmlelement
  in
  /home/virtual/site250/fst/var/www/html/employeeportal/index.php
  on line 7</p>
</blockquote>
