Everything works great with the plugin except the search box only works for users with Administrator or Editor permissions. If your permission is less it returns a 404, or searches posts rather than files. I have deactivated all other plugins with no success.
We are using the plugin as a eLearning centre for customers so the content is hidden with the plugin: Restrict Content and users must be a subscriber to view the files.
You can view the page by logging is as a subscriber
User: bob Password: bob
http://www.hirum.com.au/customer-support/elearning-centre/