[Plugin: Code Insert Manager (Q2W3 Inc Manager)] php code insert

PHP Parse error: syntax error, unexpected ‘<‘ in /var/www/wordpress/wp-content/plugins/q2w3-inc-manager/q2w3-inc-manager.php(1137) : eval()’d code on line 1

I always had this error in my Apache while I’m trying to add php code on the header of each pages…

this is the code
<?php
require_once(‘/var/www/owa/owa_php.php’);
$owa = new owa_php();
$owa->setSiteId(‘xxxxxxx’);
$owa->trackPageView();
$owa = & new owa_php;
$owa->placeHelperPageTags();
?>
But if I remove the <?php?> tag the text is just printed on the browser…
How can I execute PHP code?

http://wordpress.org/extend/plugins/q2w3-inc-manager/