I had a NT4 Domain and did an in place upgrade to 2003 Standard Server. Used the wizard and all was well. I have just purchased a 2003 Server that I would like to add as a DC and will shortly be the operations master, since the old DC will be going offline. Getting an error when I run the AD Installation Wizard on the new 2003 machine that my active directory schema is not compatible. I have read a bunch in the forums about using adprep, but it all makes mention to w2k servers. I have already raised the domain and the forest to Windows 2003. Finally my question. Do I just run the adprep on the existing 2003 DC?