For crash there is way how to solve it in topic sent by Ascathos.
What is your problem with 2 same textures... well, I am not sure. Did you create them there by accident while using texture swapper? I never managed to solve this without just deleting texturation from that chunk and painting it again, its not that big deal, well, if you have like 50 chunks in such state it is. Well, if you manage to find better, 100% working way, I would be still interrested in it.