Having Trouble with Enque Child Theme

Hi- I have spent days trying to resolve this issue, and it does not seem that anything is working. Can I get some ideas (FYI- I am super brand new to the new Enque method for Child Themes).

I am working with the Flat Responsive theme. Currently my child theme header is set up like this:

/*
Theme Name: Engage
Theme URI: https://www.ncsservices.org
Author: NCS Services
Author URI: https://www.ncsservices.org
Description: This is where we will place the theme description- can be seen by customers
Version: 1.0.0
License: GNU General Public License version 3
License URI: license.txt
Text Domain: flat-responsive
Template: flat-responsive
*/

and my current functions.php file is written like this:

<?php

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

}

I am able to load the child theme and all looks well until I go into Admin > Customize- I then get an error message on top of the screen and I am unable to make any changes via the customize panel. The error reads:

Warning: Creating default object from empty value in /home/ab1469/public_html/engage/wp-content/themes/flat-responsive/inc/customizer.php on line 174

Does anyone have idea’s of what can be causing this to happen? or can someone assist me with the child theme functions file?

I did notice that this theme has many different style sheets, I think this could be the issue, but when I attempt to maintain the parent theme dependencies as it discusses in the codex, my child theme does not show up at all. I am lost ??