When you use the search funtion, other forums are included in the results as well. This is why it’s asking for your purchase code. The demo content can be found at the top of this forum: https://support.redfactory.nl/forums/topic/demo-dummy-content-3/
I’ve updated the dummy content to be sure it works with the latest version of WordPress, but it should have been working properly. Can you try again with the updated xml file?