unable to add cookies using vb on another page

[arestech]

I'm testing and trying to get the login on a non vb page outside of the forums directory. My forums are in /forums and i want to include the login on my index page. I can get this to work with only the code below but once i add any html/php it stops working and i get the error Unable to add cookies, header already sent. tlnavbit is just a custom template i made which works..So how can i put this in my php pages? I'd really appreciate any help on this i looked through other threads about this and deleted all white spaces etc but still no luck

<?php

chdir('../forums');
require_once("./global.php");
eval('$headinclude = "' . fetch_template('headinclude') . '";');
eval('$header = "' . fetch_template('header') . '";');
eval('$tlnavbit = "' . fetch_template('tlnavbit') . '";');

echo $headinclude;
echo $header;
echo $tlnavbit;
?>