/var/www/vip6/sites/vip6314773/httpd/htdocs/wp-admin/includes/list-table.php

file from your main site to your secondary site.

I was moving a copy of the site for a customer from live to a dev environment. So was reluctant to update a couple of plugins and the latest version of WP until I had a dev. Anyways, took the plunge to backup and update. Luckily everything went fine and transferred across again. This time all worked.

Thanks for responding Naveen.