first off try this..
$sql = "SELECT forum_url from phpbb_logs";
if( !($result = $db->sql_query($sql)) )
{
message_die(GENERAL_ERROR, 'Could not query logs table', '', __LINE__, __FILE__, $sql);
}
$message='';
while ($forum_data = $db->mysql_fetch_array($result))
{
$forum_data = array_unique($forum_data);
$sitesnum=count($forum_data);
$i=0;
while ($i < $sitesnum)
{
$message.= $i." - <a href='".$forum_data[$i]."'>".$forum_data[$i]."</a><br />";
$i++;
}
}
message_die(GENERAL_MESSAGE, $message");
else try something like
$result = $db->mysql_query($sql) OR die("error: " . $db->mysql_error());
that will tell you if your getting any errors from the SQL server or not.....
(assuming you mean to use mysql_query not sql_query unless you wrote a SQL class that used the shorter name...