Adding Server 2008 to Server 2000 & 2003 as DC?

I'm running server 2000 with service pack 4 as our PDC. In addition, we are running a few server 2003 machines as member servers. We just recently lost our BDC and added a new machine running server 2008 (32 bit), also as a member server. I need to make the new server (2008) a DC. I have backed up the server 2000 system state (AD). I want to make the new server 2008 a DC so that AD will replicate and I have two DC's.

I ran adprep on the 08 server from the server 08 CD and that didn't work. Then I ran it on server 2000 and that didn't work. Server 08 tells me that I have to run adprep /forestprep. I tried that on both machines and all I get is the same message on the 08 machine: run adprep /forestprep. I did that with the same results, I don't think anything really run, all that happened is a flash of a window opening and some file activity and then it closes. Not sure where to go from here.... or how to proceed????