aheto-shortcodes-add-ons plugin / Snapster Theme

But since yesterday the plugin:
aheto-shortcodes-add-ons (which is required for theme Snapster)
is no longer running.

In July 2020, I bought Snapster Theme for Photographers @ envato
Now I had changed the content. Which it self shouldn’t be a problem.

Every time I try to reinstall the aheto-shortcodes-add-ons, I get the error message:

An error occurred while installing Aheto Shortcodes Add-Ons appears: htdocs\wp-01\wp-content\plugins\aheto-shortcodes-add-ons\index.php on line 41 Warning: Undefined array key 1

Without this plugin, the website no longer works and has crashed.
This isn’t funny, I need the site working!

How can I solve this problem?