Adding Server 2008 to 2003 Domain

Having trouble adding a windows 2008 server r2 into a win 2003 domain; the domain has 3 domain controllers (2 server 2003, 1 server 2008), all three are at win 2003 forest and win 2003 domain functional level.

I joined the new server to the domain as a member server –all is well. When I run the AD services installation wizard on the new server to “dcpromo” it to a domain controller, I get “to install a domain controller into this AD forest, you must first prepare the forest using “adprep/forestprep”. The utility is available…”

So, I go to each existing domain controller and run adprep/forestprep.  On each one, I get a favorable return “forest wide information has already been updated”.

Then I run adprep/domainprep on each one.  The 2 win2k3 servers tell me the “domain wide information has already been updated”.  On the existing 2008 server, the adprep command just returns a prompt, with no indication of anything running.

All three existing Domain controllers host the Global Catalog server.

On the new 2008 server, I ran the AD installation wizard which completes successfully.  Then,   Dcpromo fails with  the error message above.

What are my next steps?