I have some problem need help =D

salut :D a tous ^^ j'ai un prob :x pour modifier mot de passe !
j'ai rien entre il ma dit auto : "old password doesnt match" et notice: undefined index: submit

:D vasy un peut aide
im new here :D !

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Notice: Undefined index: submit in C:\Program Files\EasyPHP-5.3.8.0\www\mysite\pages\changepassword2.php on line 8
old password doesnt match!

====================

<?php
session_start();

$user = $_SESSION['username'];

if ($user){

if ($_POST['submit']){

$oldpassword = md5 ($_POST['oldpassword']);
$newpassword = md5 ($_POST['newpassword']);
$repeatpassword = md5 ($_POST['repeatpassword']);

$connect = mysql_connect("localhost","root","") or die();
mysql_select_db("forallah") or die();

$queryget = mysql_query("SELECT password from users WHERE username='$user'")or die("Query fail");
$row = mysql_fetch_assoc($queryget);

$oldpassworddb = $row['password'];

if($oldpassword==$oldpassworddb)

if($newpassword==$repeatpassword)
{

echo "success!";

}else
echo("New password don't match!");
}else{
die("old password doesnt match!");

}

echo"

<form action='changepassword2.php' method='post'>
Old Password :<input type='password' name='oldpassword' /><br/>
New Password :<input type='password' name='newpassword' /><br/>
Repeat Password :<input type='password' name='repeatpassword' /><br/>
<input type='submit' name='submit' value='change password'/><br/>
</form>";

}else{
die("You must be Logged in to change your password!");
}

?>