Script plantage

Code PHP :
<?php include("header.php"); ?>
<?php include("menusx.php"); ?>
<?php include("config.php") ?>

<?php


if(isset($_SESSION['username']) and $dnn['admin']==1 )
{
?>

<form action="modoplus.php"  method="post">
Utilisateur a faire modérateur.
<input type="text" name="ipi"  />
<input type="submit"  value="Envoyer"/></br>
</FORM>
<?php


if(isset($_SESSION['username']) and $_SESSION['username']==Admin or $_SESSION['username']==zaikoe)
{
?>

<form action="adminplus.php"  method="post">
Utilisateur a faire admin.
<input type="text" name="iaac"  />
<input type="submit"  value="Envoyer"/>
</FORM>
<?php
}
?>
<?php
}
?>


<?php include("pied_de_page.php"); ?>

Code PHP :
<?php include("header.php"); ?>
<?php include("menusx.php"); ?>
<?php include('config.php') ?>


<?php

$bonjour = $_POST['iaac']; 
?>


<?php



if(isset($_SESSION['username']) and $_SESSION['username']==zaikoe or $_SESSION['username']==Admin)
{
{
?>

<?php
$connexion = mysql_connect("***","**","**");
mysql_select_db("**",$connexion);


$caca = mysql_query("select email from users where username= '$bonjour' ");  
$cacao = mysql_fetch_array($caca);


$username = $_SESSION['username'];
$result = mysql_query("UPDATE users SET admin = 1 WHERE username = '$bonjour'");

?>


<?php

$salut = $cacao['email']; 

?>
<?php

 

 
$headers = "MIME-Version: 1.0\r\n"; 
 
$headers .= "Content-type: text/plain; charset=uft-8\r\n"; 
 
$headers .= "From: /hh/@hotmail.fr /hh/@hotmail.fr </hh/@hotmail.fr>\r\nReply-to : /h/@hotmail.fr </h/@hotmail.fr>\nX-Mailer:PHP"; 

$subject= Administration;
$destinataire="$salut"; 
$body="L'utilisateur $bonjour (vous) a  été promu administrateur BRAVO.



Cordialement l'équipe de modération de http://prizado.tk (dont vous faites partis)";

if (mail($destinataire,$subject,$body,$headers)) { 
echo "//"; 
} else { 
echo "Une erreur s'est produite"; 
} 
?>
<?php
}
?>