How to solve error problem

Hi there. I hope someone can assist me in solving this, what I have been told is a, theme related issue.

My site worked ok for a couple of months. Without any warning I started to get a white screen and could also not log in. Using the WP_DEBUG function I get the following message:

When I try to load my dutch site I get the following error.

Notice: wp_enqueue_script was called incorrectly. Scripts and styles should not be registered or enqueued until the wp_enqueue_scripts, admin_enqueue_scripts, or login_enqueue_scripts hooks. Please see Debugging in WordPress for more information. (This message was added in version 3.3.) in /mnt/web014/b0/46/56888846/htdocs/www.moedertjegroen.nl/wp-includes/functions.php on line 3792

I firstly uploaded a new functions.php file to my WP installation which I obtained from WordPress.org I was then advised in a WordPress forum that this type of error is theme related.

I renamed my old Nivana folder and uploaded a fresh copy of the theme.

I use Firefox and cleared the browser cache then typed my URL and the site appeared. All pages appeared to be ok but when I tried to login the white screen and error message appeared again. The home page also no longer appeared. I again cleared the cache and repeated the steps and everything happened exactly the same.

Does anyone have an Idea how to solve this?

By the way renaming the theme folder in the hope that wordpress will default to the standard twenty sixteen theme did not help.