CMS wont import, asking for backup

I am going through the 21 day course, and i’m importing the csv files. When i click import 3 files, it asks if i want to backup. Whatever i click, nothing happens. I click import again, same question. I dont know what to do.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

Turns out it was a bug. After a while i got an error message and sent over a report.