diff --git a/app/controllers/admin/commercials_controller.rb b/app/controllers/admin/commercials_controller.rb
index e361086d..66a1d8d7 100644
--- a/app/controllers/admin/commercials_controller.rb
+++ b/app/controllers/admin/commercials_controller.rb
@@ -65,8 +65,8 @@ module Admin
         flash[:notice] = 'Successfully added commercials.'
       else
         errors_text = ''
-        errors_text << 'Unable to find event with ID: ' + errors[:no_event].join(', ') + '. ' if errors[:no_event].any?
-        errors_text << 'There were some errors: ' + errors[:validation_errors].join('. ') if errors[:validation_errors].any?
+        errors_text += 'Unable to find event with ID: ' + errors[:no_event].join(', ') + '. ' if errors[:no_event].any?
+        errors_text += 'There were some errors: ' + errors[:validation_errors].join('. ') if errors[:validation_errors].any?
 
         flash[:error] = errors_text
       end