Enfold caused critical error

Hello,

at the moment I am not able to enter the backend of one of my pages (the frontend loads, however). I received a wordpress warning hinting the enfold theme caused a critical error (error details below).
Unfortunately, the last backup is from last month and there have been major changes to the page since.
Help is very much appreciated,

Thanks,
Manuela

Fehler-Details
==============
Ein Fehler vom Typ E_ERROR wurde in der Zeile 3767 der Datei /mnt/web506/c0/66/510401266/htdocs/STRATO-apps/wordpress_09/app/wp-content/themes/enfold/config-templatebuilder/avia-template-builder/php/class-element-templates.php verursacht. Fehlermeldung: Uncaught TypeError: Argument 1 passed to aviaElementTemplates::set_locked_attributes() must be of the type array, string given, called in /mnt/web506/c0/66/510401266/htdocs/STRATO-apps/wordpress_09/app/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/contact/contact.php on line 929 and defined in /mnt/web506/c0/66/510401266/htdocs/STRATO-apps/wordpress_09/app/wp-content/themes/enfold/config-templatebuilder/avia-template-builder/php/class-element-templates.php:3767
Stack trace:
#0 /mnt/web506/c0/66/510401266/htdocs/STRATO-apps/wordpress_09/app/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/contact/contact.php(929): aviaElementTemplates->set_locked_attributes()
#1 /mnt/web506/c0/66/510401266/htdocs/STRATO-apps/wordpress_09/app/wp-content/themes/enfold/config-templatebuilder/avia-template-builder/php/class-shortcode-template.php(1160): avia_sc_contact->shortcode_handler()
#2 /mnt/web506/c0/66/510401266/htdocs/STRATO-apps/wordpress_09/app/wp-includes/shortcodes.php(356): aviaShortc