Failed to import and invalid post types on Demo XML import
Sometimes, very occasionally the WordPress importer will refuse to import XML.
You'll notice that the author import will look like:
With "Import author: ()".
This is not normal, you should see the authors name inside the () and most of our themes have multiple authors to map.
Here is a topic on WordPress.org with more detail:
There is a simple workaround, you just need to gzip the XML file. If this is too tricky to do, please just log a ticket and we'll send you a gzipped version.