[Admin]

In misc.php, replace this:

  $minposts=0;
  $avatarbits="";

  $avatars=$DB_site->query("SELECT title,minimumposts,avatarpath FROM avatar ORDER BY minimumposts,title");

with this:

  $minposts=0;
  $avatarbits="";

  $takenids="";
  $avatarids=$DB_site->query("SELECT avatarid FROM user");
  while ($avatarid=$DB_site->fetch_array($avatarids)) {
    $takenids.=",$avatarid[avatarid]";
  }

  $avatars=$DB_site->query("SELECT title,minimumposts,avatarpath FROM avatar WHERE avatarid NOT IN (0$takenids) ORDER BY minimumposts,title");