AD Replication / Browser problem

We have a mixed network (Primary domain controllers are w2k remote sites have Win NT 4.o BDCs. We have good connectivity (TCPIP tests fine as do WINS and DNS). Users in remote sites can not change passwords. Passwords changed here do not replicatedown to remote sites. Remote servers are not visible in explorer. Servermgr shows the servers greyed out. Replmon showis itself unable to contact remote servers.

TO me it seems to be browser related, but everything seems to be ok.

What canI do to restore the ability to change passwords.