Page blank except header when I click 'Test RESTful Web Services' in my NetBeans project

I've created a Java Web Application in NetBeans. I'm using a MySQL database, a Glass Fish Server and JavaServer Faces for the project. It deploys and runs successfully. When it runs, I get the index page in my browser with links to 'Show all Customers', 'Show all Accounts' etc.

The problems occurs when I click 'Test RESTful Web Services' for the project. It opens the browser page with the correct heading (the blue header with the words Test RESTful Web Services) but the rest of the page is blank.

The project has been deployed and the server is running, so the problem's not there.

Also, I'm using the Locally Generated Test Client option so there shouldn't be an issue with my browser's security blocking access to remote resources.

I've also tried to test the RESTful Web Services/HTTP methods individually. When I right-click a method and click 'Test Resource Uri', a window pops up that says 'Unable to open resource at url...Make sure that the project has been deployed successfully and the server is running.' As I know that the project has deployed successfully and the server is running, I don't know why this doesn't work.