theres barely any code in my index.php file.??

[rY rY]

im a newbie to the 10th power my php index barely has anything in it... am I using the wrong one

<?php
include ("mainfile.php");
$index = 1;
global $menu_id,$menu,$Pmenu,$activeusers;
$Pmenu="P_thememenu_homepage";
include("header.php");
centerblocks();
echo "<br>";
// This is the referer routine from Nuke, it's handy so I left in, you
// may want to disable or remove it if you need to conserve server resources.
if ($httpref==1) {
$referer = getenv("HTTP_REFERER");
if ($referer=="" OR eregi("^unknown", $referer) OR substr("$referer",0,strlen($nukeurl))==$nukeurl OR eregi("^bookmark",$referer)) {
} else {
mysql_query("insert into $prefix"._referer." values (NULL, '$referer')");
}
$result = mysql_query("select * from $prefix"._referer."");
$numrows = mysql_num_rows($result);
if($numrows>=$httprefmax) {
mysql_query("delete from $prefix"._referer."");
}
}
// End of nuke referer
include("footer.php");
?>