I currently have 2 sites setup with a VPN. At the main Site I have a PDC running Server 2008. I am at the remote site linked with a VPN and installed AD on a new 2008 R2 server. When I try to run DCPROMO and add to an existing domain, It can see the domain but fails and says I need to run "adprep /forestprep". I pop the 2008 CD in and run command and it tells me that "ADPREP cannot run on this machine because it is not an active domain controller"
This is my first time setting up a secondary DC off-site. What step am I missing?