Pb de language sur php et mysql

<?php
header('Content-type: text/html; charset=UTF-8'); 
?>
<?php
if (isset($_POST['go']) && $_POST['go']=='Signer') {

	if ((isset($_POST['auteur'])) && (isset($_POST['email'])) && (isset($_POST['message']))) {
		if ((!empty($_POST['auteur'])) && (!empty($_POST['email'])) && (!empty($_POST['message']))) {
			$test_mail = eregi ('^[_a-z0-9-]+(.[_a-z0-9-]+)*@[a-z0-9-]+(.[a-z0-9-]+)+$', $_POST['email']);
			if ($test_mail) {
				$base = mysql_connect ('localhost', xxxx', 'xxx');
				mysql_select_db ('reuss586_or', $base);

                   


				$sql = 'INSERT INTO livre_or VALUES("", "'.mysql_escape_string($_POST['auteur']).'", "'.mysql_escape_string($_POST['email']).'", "'.date("Y-m-d H:i:s").'", "'.mysql_escape_string($_POST['message']).'")';

				mysql_query($sql) or die('Erreur SQL !'.$sql.'<br />'.mysql_error());

				mysql_close();

				header('location: livreor.php');

				exit();
			}
			else {
				$erreur = 'Votre adresse E-mail est invalide.';
			}
		}
		else {
			$erreur = 'Au moins un des champs est vide.';
		}
	}
	else {
		$erreur = 'Les variables nécessaires au script ne sont pas définies.';
	}
}
?>
<?php include("inc/hautpage.inc"); ?>
<form action="signe_livreor.php" method="post">
<table align="center">
<tr><td>
<span class="gras">Auteur :</span>
</td><td>
<input type="text" name="auteur" maxlength="30" size="50" value="<?php if (isset($_POST['auteur'])) echo htmlentities(trim($_POST['auteur'])); ?>">
</td></tr><tr><td>
<span class="gras">Adresse E-mail :</span>
</td><td>
<input type="text" name="email" maxlength="50" size="50" value="<?php if (isset($_POST['email'])) echo htmlentities(trim($_POST['email'])); ?>">
</td></tr><tr><td>
<span class="gras">Votre message :</span>
</td><td>
<textarea name="message" cols="50" rows="10"><?php if (isset($_POST['message'])) echo htmlentities(trim($_POST['message'])); ?></textarea>
</td></tr><tr><td><td align="right">
<input type="submit" name="go" value="Signer">
</td></tr></table>
</form>
<?php
if (isset($erreur)) echo '<br /><br />',$erreur;
?>
<?php include("inc/baspage.inc"); ?>