error on home page

Good Day

I seem to be getting this error on the home page of my website after I set up the poll and test it...

Warning: Cannot modify header information - headers already sent by (output started at /home/smallis/public_html/default.php:6) in /home/smallis/public_html/poll/poll_cookie.php on line 21

I have no idea wha's that about...

I tried putting the
<?php
// Important! You have to include it before your html code
include_once "/home/smallis/public_html/poll/poll_cookie.php";
?>
code.. before the <html> tag... i've tried putting it in the <head> tag...

I don't know what else to do... Can somone help please...

You can view the poll here ... www.sxmlink.com

Thanks

Alvin

has to be the very first thing on the page.