Question : How to add a 2nd DC that is an R2

I'm reading ID:23702383 and it states that you have to run adprep from the "Existing DC". I'm adding an R2 Windows Server 2003 to an existing Domain. When I do that I get the message "adprep.exe is valid but is for a machine type other than the current mabhine"  So before I continue I need clarification.

Answer : How to add a 2nd DC that is an R2

What version is your 2003 R2 disc...http://support.microsoft.com/kb/919151  found that but may not apply if you are not using that version.