Erm? Help

This is my index.php.

I have created a simple css template which I am trying to populate with wordpress functions however i am getting this error.

Can you see what is up.

<?php get_header();?>

<div id=main>
<div id=welcome>

</div>

<div id=post_box>
<?php if (have_posts()) ?>
<?php while (have_posts()) : the_post(); ?>
</div>

<div id=news></div>
<?php get_sidebar();?>
</div>

<?php get_footer();?>

If you can help I would be very grateful.

Art