diff --git a/vendor/built_in_modules/survey/app/controllers/panel/survey/back_end/surveys_controller.rb b/vendor/built_in_modules/survey/app/controllers/panel/survey/back_end/surveys_controller.rb
index 1ad95dfa6..c221df87f 100644
--- a/vendor/built_in_modules/survey/app/controllers/panel/survey/back_end/surveys_controller.rb
+++ b/vendor/built_in_modules/survey/app/controllers/panel/survey/back_end/surveys_controller.rb
@@ -1,4 +1,6 @@
 require 'csv'
+require 'iconv'
+require 'roo'
 
 # encoding: UTF-8