php4 form mailer redirect problems

[sustain]

I'm dont know much about php, but i have to have a form mailer for a site. i have found plenty of php form mailers to use. i have to use the extension php4 for it to work on the site.

the problem is that the form gets emailed but, the redirect doesnt work, it goes to a blank page where the url. ive tried several different forms with the same result.

here is the code im using:

<?

Adam Internet PHP Form Mailer v1.2

By John Edwards, Copyright September 2000.

#
#mail all variables to:
$to='[e-mail]';
while (list($key,$val) = each($HTTP_POST_VARS)){
$formmessage.="$key = $val\n";
}
#reset the from: address for a neater look
$header.="From: Papp Clinic Feedback Form <[e-mail]>\n";
#if there's an email element, use it for reply-to
if ($email)
$header.="Reply-To: $email\n";
#log the IP Address of the sender.
if ($HTTP_X_FORWARDED_FOR)
$header.="X-Originating-IP: $HTTP_X_FORWARDED_FOR via $REMOTE_ADDR\n";
else
$header.="X-Originating-IP: $REMOTE_ADDR\n";
mail($to,"Mail Form Results",$formmessage,$header);
header("Location: http://www.pappclinic.com/thankyou.htm");
?>

I would greatly appreciate any help.