Hit Counter Code giving ERROR

Hi All
I am getting an warning on my web page when I uploaded the page on server I just writing a PHP PAge Hit Counter-
<!-- Start counter code -->

<a href="http://smurf-game.com" target="blank" >
<img alt="Website counter" hspace="0" vspace="0" border="0" src="http://hitmaze-counters.net/5847121-73AB00A30823766D419F7145D3021560/counter.img?theme =1&digits=7&siteId=7"/>
</a>
<noscript><br/><a href="http://smurf-game.com">smurf-game.com</a><br>The following text will not be seen after you upload your website, please keep it in order to retain your counter functionality <br> <a href="http://www.imdb.com/video/demo_reel/vi3041172761/" target="_blank">reelhd.com</a></noscript>

<!-- End counter code -->

Here is the Code -
Counter.php

<?PHP
session_start();
if(isset($_SESSION['views'])){
$_SESSION['views'] = $_SESSION['views']+ 1;
}else{
$_SESSION['views'] = 1;
}
echo "Total page views = ". $_SESSION['views'];
?>

And I used it like this in Survey_Form.php

<div class='sfm_cr_box' style='padding:3px; width:350px'>
<?php
echo "<hr><div align=\"center\">";
include_once "counter.php"; // this will include the counter.
echo "</div>";
?>
</div>

What is the problem with the code