[PHP]Problème avec script de connexion

Bonjour,
Salut tout le monde,mon problème:
ce script emmene moi à connexion.php?probleme=1 meme si le mot de passe est correct :
<?php
include('fonctions.php');

if(isset($_POST['pseudo_entre']) && !empty($_POST['pseudo_entre']))
{
if(isset($_POST['pass_entre']) && !empty($_POST['pass_entre']))
{
if(verification_pseudo($_POST['pseudo_entre']) && verification_pass_connexion($_POST['pass_entre']))
{
$pseudo_entre = $_POST['pseudo_entre'];
$pass_entre = $_POST['pass_entre'];
$query = "SELECT * FROM users WHERE pseudo='" .$pseudo_entre. "'";
mysql_connect("localhost","root","");
mysql_select_db("users");
$don = mysql_query("$query");
$donnees_user = mysql_fetch_array($don);
$sel = $donnees_user['sel'];
$hash = $donnees_user['hash_pass'];
if(sha1($sel . $pass_entre) == $hash)
{
session_start();
$_SESSION['id'] = $donnees_user['id'];
$_SESSION['pseudo'] = $donnees_user['pseudo'];
$_SESSION['prenom'] = $donnees_user['prenom'];
$_SESSION['nom'] = $donnees_user['nom'];
$_SESSION['email'] = $donnees_user['email'];
$_SESSION['sexe'] = $donnees_user['sexe'];
$_SESSION['langue'] = $donnees_user['langue'];
$_SESSION['date_naissance'] = $donnees_user['date_naissance'];
$_SESSION['mois_naissance'] = $donnees_user['mois_naissance'];
$_SESSION['annee_naissance'] = $donnees_user['annee_naissance'];
$_SESSION['age'] = $donnees_user['age'];
$_SESSION['pays'] = $donnees_user['pays'];
$_SESSION['ip'] = $donnees_user['ip'];
$_SESSION['date_inscription'] = $donnees_user['date_inscription'];
$_SESSION['derniere_connexion'] = $donnees_user['derniere_connexion'];
header('location: index.php');
}
else
{
header('location: connexion.php?probleme=1');
}
}
else
{
header('location: connexion.php?probleme=4');
}
}
else
{
header('location: connexion.php?probleme=2');
}
}
else
{
header('location: connexion.php?probleme=3');
}
?>


aidez Moi SVP