Hi!
Thank you for the e-mail and the files!
I am still not able to import anything. I have tried disabling and even uninstalling every other plugin (except Catch Themes Demo Import and Essential COntent Types) one-by-one without success.
I have also completely restored my entire WP-installation to try again, but still no luck.
Tried setting WP_DEBUG to true in the config-file, but still only get “Error: error (500)”