lanman server as pdc or bdc

I have a situation where one of my bdc's gets displayed as a lanman server instead of as a windows nt 4.0 bdc. I tried to promote it to a pdc but that didn't help either. The problem with al this is that the system randomly locks users out and the only way to get them into the system is to restart the system or rename and recreate their account. Once in a while in server manager it will show up as a win mt 4.0 backup but only for a short period of time. any suggestions would be greatly appreciated.