анализ и исправление пользовательского кода сайта

При открытии индексной страницы сайта возникает ошибка:
Nov 20 12:44:00 vh22 apache_error: www.studio-belle.ru [Tue Nov 20 12:44:00 2018] [error] [pid 6692] sapi_apache2.c(362): [client 92.53.115.234:54216] PHP Fatal error: Uncaught Error: [] operator not supported for strings in /home/c/co67369/public_html/wp-content/plugins/LayerSlider/includes/slider_markup_init.php:83\nStack trace:\n#0 /home/c/co67369/public_html/wp-content/plugins/LayerSlider/wp/shortcodes.php(218): include()\n#1 /home/c/co67369/public_html/wp-content/plugins/LayerSlider/wp/shortcodes.php(159): LS_Shortcode::generateSliderMarkup(Array)\n#2 /home/c/co67369/public_html/wp-content/plugins/LayerSlider/wp/shortcodes.php(49): LS_Shortcode::processShortcode(Array)\n#3 /home/c/co67369/public_html/wp-content/plugins/LayerSlider/wp/shortcodes.php(5): LS_Shortcode::handleShortcode(Array)\n#4 /home/c/co67369/public_html/wp-content/themes/tribute/header.php(97): layerslider(1)\n#5 /home/c/co67369/public_html/wp-includes/template.php(688): require_once('/home/c/co67369...')\n#6...