Small Business Server 2000 as BDC!

I have started to setup a SBS 2000 as a backup domain controller using a PC.I was asked by the setup to demote the server by running dcpromo.exe.
I did that and the rest of the setup goes well but at the end of the setup I get this message: “This product does not support this option”.
Does that mean that SBS 2000 can not be setup as a Backup Domain Controller on a PC?