Fatal error: Call to undefined function: simplexml_load_string() in C:\Users\Mazur\Downloads\OTS\Dodatki\Acc Maker\includes\spells.php on line 12

 <?
$root = "$data_folder";

$f = @file_get_contents($root . "\\spells\\spells.xml");

if($f === FALSE)
    {
    echo "<b>Niepoprawna ¶cie¿ka do katalogów, popraw to w configu!</b>";
    }
else
    {
    $XML = simplexml_load_string($string);
    echo 'Czary na serverze: (Niektóre czary sa dostêpne tylko dla potworów.)<br><br>
    <table border="1" align="center" width="90%" bordercolordark="black" bordercolorlight="black" class="mon">  
    <tr> 
    <th width="60%">Spell name:</th><th width="20%">Mana</th><th width="20%">Magic level</th> 
    </tr>'; 
    
    foreach($XML->spell as $spell) 
        { 
        if($spell['enabled'] == 0) continue; 
  
        echo "<tr> 
        <td width=\"60%\">".$spell['name']."    (".$spell['words'].") </td> 
        <td width=\"20%\">".$spell['mana']."</td> 
        <td width=\"20%\">".$spell['maglv']."</td> 
        </tr>"; 
        }
    echo "</table>"; 
    }    
?>