reports_controller.rb

def index
  #...
  
  current_page      = (params[:page] || 1)       # <--- I probably should just 'to_i' both current_page and per_page
  per_page          = (params[:per_page] || 25)  # <---

  #...

  @reports = WillPaginate::Collection.create(current_page, per_page, @results.count) do |pager|

    start = (current_page.to_i-1)*per_page  # <---- the problem was here.  current_page can be a String.
    pager.replace( @results[start, per_page] )

   end

   #...

end