Qu'est ce qu'il faut à ce code ?????

bonjour

<?php require('Connections/essai1.php'); ?>
<?php

if (isset($_POST['pseudo']) && isset($_POST['password']))
{
if (($_POST['pseudo'] != NULL) && ($_POST['password'] != NULL ))
{
$pseudo=$_POST['pseudo'];
$password=$_POST['password'];

mysql_select_db($database_essai1);
$query="SELECT login,passe FROM user WHERE login='$pseudo' and passe='$password' ";
$result= mysql_query($query) or die(mysql_error());
$row_result= mysql_fetch_assoc($result);

if ($row_result) {
header("Location: gestion_clients.php" );
}
else {
header("Location: acceuil.php");
}
}
}