Critical Error but not, Failed import

I have spent three days trying to get this to work. It fails. Says there is a critical error on my website, but there’s not. I received one email with the following info

Error Details ============= An error of type E_ERROR was caused in line 209 of the file /home1/illusip1/public_html/annedallrobson/wp-content/plugins/import-html-pages/html-importer.php. Error message: Uncaught TypeError: mb_strrpos(): Argument #3 ($offset) must be of type int, string given in /home1/illusip1/public_html/annedallrobson/wp-content/plugins/import-html-pages/html-importer.php:209 Stack trace: #0 /home1/illusip1/public_html/annedallrobson/wp-content/plugins/import-html-pages/html-importer.php(209): mb_strrpos(‘/home1/illusip1…’, ‘/’, ‘UTF-8’) #1 /home1/illusip1/public_html/annedallrobson/wp-content/plugins/import-html-pages/html-importer.php(842): HTML_Import->remove_dot_segments(‘/home1/illusip1…’) #2 /home1/illusip1/public_html/annedallrobson/wp-content/plugins/import-html-pages/html-importer.php(1001): HTML_Import->import_images(215, ”) #3 /home1/illusip1/public_html/annedallrobson/wp-content/plugins/import-html-pages/html-importer.php(1079): HTML_Import->find_images() #4 /home1/illusip1/public_html/annedallrobson/wp-content/plugins/import-html-pages/html-importer.php(1128): HTML_Import->import() #5 /home1/illusip1/public_html/annedallrobson/wp-admin/admin.php(364): HTML_Import->dispatch() #6 {main} thrown

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