WordPress single.php Page

<?php get_header();?>
<div class="maincontent">
<?php get_sidebar();?>
<div class="content">

<?php if(have_posts()) : ?><?php while(have_posts())  : the_post(); ?>
<h2><?php the_title(); ?></h2>
<a href="<?php the_permalink(); ?>"><?php the_post_thumbnail('single-post-image', array('class' => 'single-post-thumb')); ?></a>
<?php the_content(); ?>
 <?php comments_template( '', true ); ?>
<?php endwhile; ?>
<?php else : ?>
<h3><?php _e('404 Error&#58; Not Found'); ?></h3>
<?php endif; ?>

</div>
</div>
<?php get_footer();?>