Unable to display an image from custom field value

I’m unable to display an image using the custom value fields, it worked before i updated to wordpress 2.8.4, now it only displays the border where the image should be. Site is here
Code used to display image from custom field. I’m TimThumb to re-size images.

$preview = get_post_meta($post->ID, 'preview',true);
	$date = get_post_meta($post->ID, 'date',true);
	?>

	<div class="work <?php if($counter == 2) { echo "last"; $counter = 0; }; ?>">

		<?php if($preview) { ?>
			<a href="<?php the_permalink(); ?>">
				<img src="<?php bloginfo('template_directory'); ?>/inc/thumb.php
				?src=<?php echo $preview; ?>&w=450&h=210&zc=1&q=100"
				 alt="<?php the_title(); ?>" />
			</a>
			<?php
		} ?>

Any ideas on how to fix this problem would be greatly appreciated!