Added ave and craig

src/dawn/games/vn/events/VNSetEvent.hpp

@@ -15,7 +15,7 @@ namespace Dawn {
 
     protected:
       void onStart() override {
-        assertNotNull(this->modifies);
+        assertNotNull(this->modifies, "VNSetEvent::onStart() modifies is null!");
         *modifies = value;
         this->next();
       }