It is hard to tell exactly what is going on here, but the "no items" error can happen when someone who does not have access to a site folder tries to open it directly. If you are the one that created the site, and you created it in the Share UI, then this should not be happening, obviously.
The dashlet error is often displayed when SOLR is having problems.
Are you seeing that dashlet error in all of your siites?
Is SOLR able to index and query for new content?
Can you create folders successfully in other sites? What about in the repository (outside of a site)?