Feral Heart

I've been having this problems for days. I CAN login with my username and password, can create characters but when I click on 'start', it quits. I've tried creating other many characters, neither of them worked. I remember that I had another username (I'd tried to delete it before I created my new one but I didn't know how to do it, so I kept it), tried to play with that and it works perfectly. Why can't I play with THIS username? Please help, and if you can help me with deleting my other account (because I don't want to have many accounts...), I'd be so happy.