Hi John,
thanks for your post, and sorry for the trouble.
The reason for this seems to the URL rewriting that WP Super Cache performs.
For example, it converts the URL of the TablePress default CSS file to
http://static.larkin.net.au/wp-content/plugins/tablepress/css/default.min.css
However, the server only returns a "404 Not found" error for that URL. If I however change the "static" at the beginning to "www", the file is returned, as expected.
The same happens for the WordPress core JS file http://static.larkin.net.au/wp-includes/js/comment-reply.min.js
So, my assumption is that something in the WP Super Cache or server configuration (regarding the URL rewriting) is not set up properly.
Regards,
Tobias