Problems with functions.php and echo do_shortcode

Hi!

I am struggeling now over 3 weeks, and I think I have the same problem as shown here.

I don´t have the big experience with the functions.php.
When I click on a button on my side, ajax is calling an action in my functions.php, and the “echo do_shortcode(‘[envira-gallery id=”38767″]’);” delivers back the gallery.
But, when I click on one picture, I have the same problem as described above in the link.

How do I emplement the code from the solution into my functions.php?
I have downloaded the newest version of the bootstrap and stored it in the same folder as the functions.php lies:

function pwwp_enqueue_my_scripts() {
// jQuery is stated as a dependancy of bootstrap-js – it will be loaded by WordPress before the BS scripts
wp_enqueue_script( ‘bootstrap-js’, ‘../wp-content/themes/fk-kronborg-divi/bootstrap.bundle.min.js’, array(‘jquery’), true); // all the bootstrap javascript goodness
}
add_action(‘wp_enqueue_scripts’, ‘pwwp_enqueue_my_scripts’);

But it doesn¨t help/work.

Would anybody please be so kind and help me with that?
Thanks in advance!
Martin.