Classic Contemporary Green Has me Locked in Template Selection

I'm using 1.39h version of Zen Cart,
My problem is classic contemporary green (default)has me locked in and i can't change my template. I looked through the forum and have tried to find someone who has had this problem also. Any suggestions are welcomed to fix this problem:(

Has your copy of template_info.php been deleted from your_template name?

template info.php is there and intact

To change your website and admin panel for this:> admin panel/ tools/ template selection

haredo:

To change your website and admin panel for this:
I'm doing that correctly , for some reason classic default will not let me load my new gti template, i go to check the page and this what im getting on google chrome

Server error
The website encountered an error while retrieving https://northstateproducts.com/index.php?main_page=. It may be down for maintenance or configured incorrectly.
Here are some suggestions:
Reload this web page later.
HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.

Report back any errors in this folder please: > root directory/ cache
And
https://www.zen-cart.com/tutorials/index.php?article=63