Conflit d'encodage

Bonjour a tous,

Je viens de "finir" une site/forum et j'aimerais introduire les dernier post du forum sur la page d'accueil, ne vous en faites pas je sais comment on fait.

En fait toutes les pages sont en utf-8, et avant que je fasse :

<?php include('forum_lastpost.php'); ?>

.. la page comprend bien les accents, etc.. Cependant dès que j'inclus cette page, toute la page passe en Iso, excepter cette include, forum_lastpost.php :

<?php
mysql_connect(DB_HOST,DB_LOGIN,DB_PASS);
mysql_select_db(DB_BDD);
?>

        <table class="tablebg" cellspacing="1" width="100%">
<tbody>
        <tr>
                <th colspan="2"> Derniers Messages </th>
                <th> Auteurs </th>
        </tr>
<?php
define('IN_SITE', true);
define('IN_PHPBB', true);
$phpbb_root_path = './forum/';
$phpEx = substr(strrchr( __FILE__ , '.'), 1);
include($phpbb_root_path . 'common.' . $phpEx);
// Sélection des 10 derniers posts
$sql = "SELECT t.topic_replies_real,t.topic_replies,t.topic_title,t.forum_id,t.topic_id,t.topic_type,t.topic_last_post_id,f.forum_name,t.topic_last_poster_name,t.topic_last_post_time
FROM " . TOPICS_TABLE . " t, " . FORUMS_TABLE . " f
WHERE t.topic_approved = 1 
AND t.topic_status <> 2
AND t.forum_id = f.forum_id
ORDER BY t.topic_last_post_time DESC 
LIMIT 3";
$result = $db->sql_query($sql);
// Boucle d'affichage du post
while($topic_data = $db->sql_fetchrow($result)) 
{
    // Données du topic
    $topic_title = $topic_data'topic_title'];
    $topic_replies = $topic_data'topic_replies'];
    $topic_replies_real = $topic_data'topic_replies_real'];
    $forum_id = $topic_data'forum_id'];
    $topic_id = $topic_data'topic_id'];
    $forum_name = $topic_data'forum_name'];
    $topic_last_post_id = $topic_data'topic_last_post_id'];
    $topic_last_post_time = $topic_data'topic_last_post_time'];
    $topic_last_poster_name = $topic_data'topic_last_poster_name'];
       $replies = ($auth->acl_get('m_approve', $forum_id)) ? $topic_replies_real : $topic_replies; 
    $start = floor(($replies) / $config'posts_per_page']) * $config'posts_per_page']; 

    $post_url = append_sid("http://forum.race-end-velocity.com/viewtopic.$phpEx", 't=' . $topic_id . '&f=' . $forum_id . '&start=' . $start ) . '#p' . $topic_last_post_id; 
    $topic_url = append_sid("http://forum.race-end-velocity.com/viewtopic.$phpEx", 't=' . $topic_id . '&f=' . $forum_id ); 

echo '
            <tr>
            <td class="row1" width="50" align="center"><img src="./forum/styles/1Game/imageset/forum_unread.gif" width="27" height="27"></td>
            <td class="row1" width="100%">
                                <div><a class="forumlink" href="'.$topic_url.'">'.$topic_title.'</a></div>
                                                                <div>Catégorie : '.$forum_name.'</div>
                            </td>
            <td class="row2" align="center" nowrap="nowrap">
                                    <div class="topicdetails">'.strftime('%d/%m/%y ',$topic_last_post_time).' à '.strftime('%H:%M ',$topic_last_post_time).'</div>
                    <div class="topicdetails">'.$topic_last_poster_name.' <a href="'.$post_url.'"><img src="./forum/styles/1Game/imageset/icon_topic_latest.gif" width="18" height="9" alt="Voir le dernier message" title="Voir le dernier message"></a> </p>
                            </td>
        </tr>';
}
$db->sql_freeresult($result);
?>
</tbody>
    </table>
            </div>
            <div class="bottom"></div>

            <div class="top"></div>
            <div class="article">

Je voudrais donc comprendre ce qui, dans ce code, fait que la page se décode... :S