Hi simon-1553,
Thank you very much for choosing our theme and for contacting us.
I recommend executing the import on a new WordPress installation. You can accomplish this by using the WordPress Database Reset plugin, which can be found at https://wordpress.org/plugins/wp-reset/. This plugin enables you to erase all existing content and install a fresh version.
Furthermore, I encourage you to adhere to our theme documentation available at https://xtemos.com/docs-topic/installation-process/
In the bottom of the page, you will find a video tutorial. If you have any questions please feel free to contact us.
Regards,