Post Type Problem

[ Moderator note: title adjusted, please refrain from using help, urgent, emergency, asap, etc. in topic titles. ]

Hello,

I have created custom post type “book“. I want to show that custom post type in my index.php file. I’m using this code:

<?php
	$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;	
	$wp_query = new WP_Query( array(
		'post_type' => array( 'book' ),
		'posts_per_page' => 5,
		'paged' => $paged,
	));
?>
<?php if ( $wp_query->have_posts() ) : ?>
<?php while ( $wp_query->have_posts() ) : $wp_query->the_post(); ?>

<?php echo get_the_title(); ?>

<?php endwhile; ?>	
<div class="pagination">
	<div class="nav-previous alignleft"><?php next_posts_link( 'Older posts' ); ?></div>
	<div class="nav-next alignright"><?php previous_posts_link( 'Newer posts' ); ?></div>
</div>
<?php wp_reset_query(); wp_reset_postdata(); ?>
<?php else : ?>
<?php endif; ?>

I get a 404 error on page 2 every time. Can someone help me, please!

Thank you

[ Bumps deleted. No bumping please. ]