FATAL ERROR

Hello everyone and thanks in advance for the solution. Excuse me if you have already talked about it, but I have not seen among the various comments.
I inserted a tab on my website http://www.fucineassolute.com and I got:

Details of the error
====================
An E_ERROR error was caused in line 552 of the /web/htdocs/www.fucineassolute.com/home/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/tabs/tabs.php file. Error message: Uncaught Error: Cannot access protected property avia_sc_toggle :: $ counter in /web/htdocs/www.fucineassolute.com/home/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/tabs/tabs. php: 552
Stack trace:
# 0 /web/htdocs/www.fucineassolute.com/home/wp-includes/shortcodes.php(343): avia_sc_tab-> av_tab ()
# 1 [internal function]: do_shortcode_tag ()
# 2 /web/htdocs/www.fucineassolute.com/home/wp-includes/shortcodes.php(218): preg_replace_callback ()
# 3 /web/htdocs/www.fucineassolute.com/home/wp-content/themes/enfold/config-templatebuilder/avia-template-builder/php/shortcode-helper.class.php(484): do_shortcode ()
# 4 /web/htdocs/www.fucineassolute.com/home/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/tabs/tabs.php(499): ShortcodeHelper :: avia_remove_autop ()
# 5 /web/htdocs/www.fucineassolute.com/home/wp-content/themes/enfold/config-templatebuilder/avia-template-builder/php/shortcode-template.class.php(891): avia_sc_tab-> shortcode_handler ()
# 6 /web/htdocs/www.fucineassolute.com/home/wp-includes/sh
How can I fix it? I was able to restore the site, but if I go to edit page from WP, it writes me many error lines and I can’t make any changes. I wanted to work on the .php files, but I’m afraid of doing damage! Help :-)