When placing <?php include 'accesscontrol.php'; ?> at the begiining of my file I get the below error message. Any ideas ?

Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /home/joe/webname-www/gallery/index.php:2) in /home/joe/phpincludes/accesscontrol.inc on line 5

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /home/joe/webname-www/gallery/index.php:2) in /home/joe/phpincludes/accesscontrol.inc on line 5


***********Code from Kevin Yanks article************
<?php // accesscontrol.php
include_once 'common.inc';
include_once 'db.inc';

session_start();
$uid = isset($_POST['uid']) ? $_POST['uid'] : $_SESSION['uid'];
$pwd = isset($_POST['pwd']) ? $_POST['pwd'] : $_SESSION['pwd'];

if(!isset($uid)) {
?>
<!DOCTYPE html PUBLIC "-//W3C/DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title> Please Log In for Access </title>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1" />
</head>
<body>
<h1> Login Required </h1>
<p>You must log in to access this area of the site. If you are
not a registered user, <a href="signup.php">click here</a>
to sign up for instant access!</p>
<p><form method="post" action="<?=$_SERVER['PHP_SELF']?>">
User ID: <input type="text" name="uid" size="8" /><br />
Password: <input type="password" name="pwd" SIZE="8" /><br />
<input type="submit" value="Log in" />
</form></p>
</body>
</html>
<?php
exit;
}
$_SESSION['uid'] = $uid;
$_SESSION['pwd'] = $pwd;

dbConnect("sessions");
$sql = "SELECT * FROM user WHERE
userid = '$uid' AND password = PASSWORD('$pwd')";
$result = mysql_query($sql);
if (!$result) {
error('A database error occurred while checking your '.
'login details.\\nIfhis error persists, please '.
'contact admin@website.com.');
}
if (mysql_num_rows($result) == 0) {
unset($_SESSION['uid']);
unset($_SESSION['pwd']);
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title> Access Denied </title>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1" />
</head>
<body>
<h1> Access Denied </h1>
<p>Your user ID or password is incorrect, or you are not a
registered user on this site. To try logging in again, click
<a href="<?=$_SERVER['PHP_SELF']?>">here</a>. To register for instant
access, click <a href="signup.php">here</a>.</p>
</body>
</html>
<?php
exit;
}
$username = mysql_result($result,0,'fullname');
?>