Well, I tried several password from 5 to 13 caracteres, it doesn't work. One thing strange is that I tried to make it work on two servers, one at my office, one at home. At the begining, the two servers wasn't able to be a pdc. Last week, I've done a fresh install on my home server, I reconfigure exactly the same way and then, it works (even with a 16 caracteres admin's password). the one at my office still don't. I'm trying to figure out why. I will post if I find the difference between the two server.