Undefined variable functions.php

Hi

I get the following message on my site: Notice: Undefined variable: zerif_lite_sidebars in /home3/thougjk5/public_html/wp-content/themes/zeriflite_child/functions.php on line 12

code:

<?php
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
function theme_enqueue_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );

}
add_theme_support('custom-background', apply_filters('zerif_custom_background_args', array(
        'default-color' => 'ffffff',
        'default-image' => get_stylesheet_directory_uri() . "/images/khiva3.jpg",
    )));

	if ( empty ( $active_widgets[ $zerif_lite_sidebars['sidebar-ourfocus'] ] ) ):

		$zerif_lite_counter = 1;

The message appeared after I changed WP DEBUG to true in wp-config.php.

Any help would be be appreciated.

Thanks
Simon