Hi, DKA, and welcome!
The first thing I know all the regulars are going to suggest is to make sure he doesn't have a bladder infection or other illness (i.e. vet visit). Assuming he is 100% healthy, if a dog is not potty trained, hours they can hold it don't matter for the training - does "frequently" mean taking him out every 30 minutes to 1 hour, and rewarding heavily (high value food) when he does his business outside? If not, he may not have enough incentive at this point to go potty outside consistently, and is making mistakes inside because taking him out every 3 or 4 hours is too long for him. You may want to read the housebreaking thread:
House Training How Tos:. Also, if it seems like he's peeing 30 minutes to an hour after pooping, you might want to start taking him out every 15 minutes after pooping until he pees. The goal is to make him realize he gets great rewards outside for pottying, but nothing inside - so the less mistakes inside and more rewards outside the easier he'll understand.
Also, he's most likely barking in the crate because he doesn't like sitting in pee, not to notify you of his mistake!

If my dog has an accident in his crate (very rarely at this point - he is potty/crate trained), he will definitely let us know!
I hope that helps a bit.