Tu dois changer l'ID du forum.

<div class="blockform">
    <h2><span>Déplacer la discussion à la corbeille</span></h2>
    <div class="box">
    <form method="post" action="moderate.php?fid=<?php echo $fid ?>">
        <input type="hidden" name="topics" value="<?php echo $topics ?>" />
        <input type="hidden" name="move_to_forum" value="40" />
        <input type="submit" name="move_topics_to" value="Déplacement Rapide" />
    </form>
    </div>
</div>