UE4 Shipping Config Crashes on Other computers

I am developing a game with UE4. I package the project for shipping and development. It works fine on my pc and one of my testers. However, another one of my testers is unable to open the game. He gets this error window:


The UE4-Light Game has crashed and will close

Fatal error!


I’v tried changing the packing config and it still wont work. Please help!