Training a dog when they are scared is a difficult/impossible task. That's just not how the brain works. When the fear overloads the brain and body with the chemicals that naturally occur in that condition, learning doesn't occur.
You need to immediately get in touch with a veterinary behaviorist. These situations can usually be dealt with by combining drugs that moderate the brain activity to minimize or lessen the fear response combined with the training. Just training alone, or just medication alone is not the best way forward.
Doug, DVM