need help vbulletin/ seperate php script

[Vizionz]

Stand alone script trying to get stylesheet not working

will call this little code CODE 1

<?
session_start();
require "common.php";
?>

that call will access a file that has this info in it


THIS IS CODE2 Also known as the common.php file

<?php

function connectdbase() {
$db = mysql_connect("localhost", "username", "pass");
mysql_select_db("dataname",$db);
}

?>

This is where i have my problem.. if i put this in the php code with the CODE 1 snippet i end yup with Unable to add cookies, header already sent
So where would this problem becoming from. why would the two conflict

<?
chdir('/home/Forum);
require_once('./global.php');
?><? echo $style['css']; ?>