I was just toying around with that program in a VM last week to see how it worked. Can't remember how I got card decks installed, so just did it all in a VM again.
You can install the version from the repositories, or the deb file of latest version directly off of their site?
I used the deb file from their site:
http://ankisrs.netThe only things I tested out were two Spanish language sets from here:
https://ankiweb.net/shared/decks/I downloaded them to Downloads folder; opened Anki program and clicked "Import File" button along bottom of window; selected one file at a time and hit "Open". They then showed up as decks in the interface to be used. Try doing it that way. (Don't extract the downloaded files first; just import them as they are when downloaded.)