[Plugin: WP Widget Cache] Gives problem

Do not ask me much details, as I am not good at PHP. I added following to widget-cache.php before any existing code:
<?php

// Above Headers Sent By PHP.

session_cache_limiter( ‘nocache’ );

// Start Session.

session_start( );

// Override Headers.

header( ‘Cache-Control: no-cache, must-revalidate, post-check=3600, pre-check=3600’ );

?>
Every thing is normal in IE9 and IE8.