Adva poll show Warning: Cannot modify header information

I found this warning at the top of my adv Poll page after vote :

Warning: Cannot modify header information - headers already sent by (output started at /home/wanida/public_html/indexcoba.php:2) in /home/wanida/public_html/poll/poll_cookie.php on line 21

How to fix it ?

try this...

http://proxy2.de/forum/viewtopic.php?t=3423

- Auron

Hello,

I've read the above fixit, but still can't get rid of this error message once someone votes:

Warning: Cannot add header information - headers already sent by (output started at /var/www/html/ca/camdenboatworks.com/index.php:5) in /var/www/html/ca/camdenboatworks.com/poll/poll_cookie.php on line 21

The top of my header.php reads:

<?php
include_once "/var/www/html/ca/camdenboatworks.com/poll/poll_cookie.php";
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Expires" content="Wednesday, 03-Sep-2003 10:35:03 GMT">
<meta http-equiv="Content-Type" content="txt/html; charset=ISO-8859-1">
<meta http-equiv="Content-Language" content="en">
<title>Yacht Management and Consulting, Ocean Deliveries, Boat Repair and Wooden
Boat Restoration</title>

Any help please.

Thanks,

Greg