related files appear to be missing / corrupt from your forum's admin folder - run files verification from tools & maintenance
It just says changed or missing.
Doesn't show a file with a name like database. :/
there is no file with name database. you have to check for files in admin folder (../admin/...)
Try re-uploading the contents of the language and admin folders from a fresh MyBB download.
Thank you so much euantor!