Warning: require_once(passwordprompter.class) [function.require-once]: failed to open stream: No such file or directory in F:\www\wamp\www\...\auth-OO.php on line 2

Fatal error: require_once() [function.require]: Failed opening required 'passwordprompter.class' (include_path='.;C:\php5\pear') in F:\www\wamp\www\...\auth-OO.php on line 2

<?php
require_once("passwordprompter.class");
require_once("database.class");
require_once("account.class");
require_once("webpage.class");

//Regarde si l'utilisateur a ete invite a entrer son nom
if (isset($_SERVER['PHP_AUTH_USER']))
{
    try
    {
        $prompter = new passwordprompter("Partie secrète");
        $prompter->displayprompt();
    }
    catch(Exception $e)
    {
        echo $e->getmessage();
        exit();
    }
}
.....

<?php
class passwordprompter
{
    private $realm;

    function __construct($realm)
    {
        if (is_string($realm))
        {
            $this->realm = $realm;
        }
        else
        {
            throw new Exception ("Cet argument doit etre un chaine");
        }
    }

function displayprompt()
{
    header("WWW-Authenticate : Basic realm=\"$this->realm\"");
    header("HTTP/1.1 401 Unauthaurized");
    exit("Cette page nécessite une authentification!");
}
}
?>