[Plugin: Search Suggest] Troubleshooting

I have painting website http://artpaintingartist.org where i sometime needs to update images so if any user is coming to visit old image that url shows “error 404 not found”

Here is example URL http://artpaintingartist.org/wordpress-jpg

I tried to use this plugin
http://yoast.com/wordpress/search-suggest/
I have installed it and inserted suggested code in 404.php file. but it wasn’t suggesting similar search options.

Here is code from 404.php

<?php get_header(); ?>
<?php if ($options['mts_layout'] == 'cslayout' || $options['mts_layout'] == 'sclayout') { ?>
<?php } else { ?>
<div id="sidebar-left" class="left-menu">
<?php if ( ! dynamic_sidebar( 'Left Sidebar' ) ) : ?>
<?php endif ?>
</div>
<?php } ?>
<div id="content" class="hfeed">
	<div id="error404" class="post-single post_box">
	<header>
	<div class="post headline_area">
		<h1><?php _e('Error 404 Not Found', 'mythemeshop'); ?></h1>
	</div>
	</header>
		<div class="post-content">
			<p><?php _e('Oops! We couldn\'t Found this Page.', 'mythemeshop'); ?></p>
			<p><?php _e('Please check your URL or use the search form below.', 'mythemeshop'); ?></p>
			<?php get_search_form();?>
		</div><!--.post-content--><!--#error404 .post-->
	</div>
</div><!--#content-->
<?php get_sidebar(); ?>
<?php get_footer(); ?>

if you have used this plugin, so pls. let me know how to suggest similar search on 404.php

Thanks