custom background feature not working

I am new to WordPress but not new to designing and theming. I have just started a wordpress theme the other day and when working on the custom background of a naked theme I have been unable to to get it to work.

functions.php

//Code for custom background support
add_custom_background();

header.php

<?php
	/*
	 * 	Add this to support sites with sites with threaded comments enabled.
	 */
	if ( is_singular() && get_option( 'thread_comments' ) )
		wp_enqueue_script( 'comment-reply' );

	wp_head();

	wp_get_archives('type=monthly&format=link');
?>

After adding this I went to the backend and clicked on appearance then background of my already active theme and upload a custom background, sadly the page only uses the body style for the page. I have managed to preform this without problems on themes that come with WordPress but not my own. No changes have been made to WordPress at all.

Any help on this please and thank you