My app was already using will_paginate extensively and I didn’t feel like changing it all to the Kaminari which ActiveAdmin uses for pagination.
However, somehow I was able to get it to work by thumbing through this ActiveAdmin issue. I created the initializer suggested by kml with this code:
Kaminari.configure do |config|
config.page_method_name = :bonzo # :)
However, when I implemented it, the code recommended for config/initializers/active_admin.rb caused me errors so I removed it. You may find that you need this code.