No add to cart button on variable item in woocommerce

Using a premium theme from the MOJO marketplace: TemplateMela Apparel Store for woocommerce.

I have tried adding the following code to the functions.php file. I first did it in a child theme and that seemed to have no effect. When I added it directly into the theme’s original functions file, that caused a php error.

function mv_my_theme_scripts()
{
wp_enqueue_script('add-to-cart-variation', plugins_url() . '/woocommerce/assets/js/frontend/add-to-cart-variation.js',array('jquery'),'1.0',true);
}
add_action('wp_enqueue_scripts','mv_my_theme_scripts');
?>