Brushes not working in the air app

Hi, the bell pepper brushes have never worked for me in the Air app, but they do work when I open Flockmod in Chrome. When I try to load brushes in the air app, it just says "Wrong file type" on every .gbr I try to load, regardless of whether the file size is smaller or larger than 1 MB. Even the brushes on http://py-bot.com/gimpbrushes.zip all fail to work in the Air app. I'm using a Mac, if that helps.