I updated and then checked the code and saw you changed the function so I dont have to anymore.
Nope, I didn't. This is what's happening:
Fatal error: Call to a member function get_default_language() on a non-object in /absolute/path/to/wp-content/plugins/wordpress-popular-posts/wordpress-popular-posts.php on line 1361
WPP isn't collecting any data because of Polylang. Make sure you make the change I suggested before. I may add an extra check for Polylang on a future release so you don't have to manually patch it everytime.