Change "_filename" to "_identifier" for carrierwave

app/controllers/admin/purchases_controller.rb

@@ -172,7 +172,7 @@ class Admin::PurchasesController < ApplicationController
   
   
   def build_file(orig_zip, zip_name, dir, object, type = nil)
-    title = object.file_filename
+    title = object.file_identifier
     temp = File.new(dir + '/' + title, 'w+')
     temp.write orig_zip.read(zip_name + '/' + (type ? (type + '/') : '') + title)
     object.file = temp