I think the pup's behaviour is normal for that age. It wants to be with the rest of the 'pack' and doesn't understand why it can't. There's a thread here I read about establishing yourself as pack leader. As leader you have the right to tell the rest of the pack what they need to do, and that includes putting them in the crate. Pack behaviour is instictive in dogs and can be used to your advantage in this situation. There are several books out on the subject, too.