WP Download Manager

I installed WP Download Manager about two days ago. After successfully creating a package, I am not able to delete it in the “manager” section of the plugin. I have tried clicking both “delete permanently” link directly under the package name as well as checking the package name and trying to use the “delete” bulk action. In both cases, the popup to confirm the delete action is displayed. After clicking “ok”, the screen refreshes to a mostly blank page with URL: http://www.illinoisincludes.org/wp-admin/admin.php?page=file-manager&task=wpdm_delete_file&id=2

While most of the page is empty, the WordPress menu on the left side and along the top is visible. When I navigate back to the File Manager menu, the file is still displayed.

https://ww.wp.xz.cn/plugins/wp-downloadmanager/