Backup active directory server

Hi,
I’m running 2 active directory servers in my network. We are busy with a disaster recovery setup so we want to have a 3th active directory server on a remote location. I installed a win2003standard server, I performed DC promo.
My 2 other servers see the new domain controllor. So this is working fine.
But I have a strange issue.
When I turn of the new server. I can’t logon to the network anymore. (login script can’t map the network drives)
Does anyone had this problem before? Or knows the solution.
Leaving the server powered on is no option. Because when there is a failure between the office and the disaster recovery location I will have a big issue…

thanks in advance