Fatal error: Uncaught Error: Call to undefined function validate_current_theme() in /srv/drbd-web/home/chelix/public_html/wp-content/plugins/all-in-one-event-calendar/public/admin/themes-install.php on line 1

Error: Call to undefined function validate_current_theme() in /srv/drbd-web/home/chelix/public_html/wp-content/plugins/all-in-one-event-calendar/public/admin/themes-install.php on line 1

Call Stack:
    0.0015     360520   1. {main}() /srv/drbd-web/home/chelix/public_html/wp-content/plugins/all-in-one-event-calendar/public/admin/themes-install.php:0