...
$guid = addslashes($_GET["guid"]);
...
$sql = "SELECT guid, account, CAST(SUBSTRING_INDEX(SUBSTRING_INDEX(`data`, ' ', 1462), ' ', -1) AS UNSIGNED) AS `money`, name FROM characters WHERE guid=$guid AND account=$id";
...

...
$_GET['page'] = !isset($_GET['page'])?'guilds':$_GET['page'];
...
include("./module/".$_GET['page'].".php");
...

...
if (@$_GET['guid']) {
$guildid = addslashes($_GET['guid']);
...
$query_leader_name = $characters_db->query("SELECT * FROM `characters` WHERE `guid` IN (SELECT `guid` FROM `guild_member` WHERE `guildid`=".$guildid.") ORDER by `name`");
...

<?php
if (!$menu = &$_GET['page']) 
$menu=$main_page;
print "<table align=\"center\" valign=\"top\" cellSpacing=\"0\" cellPadding=\"0\" width=\"100%\" border=\"0\" ><tr>
<td width=\"100%\" valign=\"top\" align=\"center\" >";
require_once("modules/$menu.php");
print "</td></tr></table>";
?>