Da fehlt noch einmal " im Link, evtl lags daran:

PHP-Code:
<marquee scrollamount="2" scrolldelay="5" onmouseover="this.setAttribute('scrollamount', 0, 0);" onmouseout="this.setAttribute('scrollamount', 2, 0);">
<?php
$newpost = db_query("SELECT * FROM vms_forum_topics ORDER BY topic_last_post_time DESC LIMIT 5");
while ($row = mysql_fetch_array($newpost)) {
  echo '<a href="?content=/forum/showtopic&fid='.$row['forum_id'].'&tid='.$row['topic_id'].'">'.$row['topic_title'].'</a> Letzter Beitrag von: '.$row['topic_last_post_name'].' am: '.date('d.m. H:i',$row['topic_last_post_time']).' | ';
}
?>
</marquee><br><br>