The Source Server that is running Windows SBS 2003 (<<servername>>) still exists in the Active Directory Sites and Services in the Default-First-Site-Name. You should remove this server from AD Sites and Services after you demote the server and remove it from the domain.
This is what I get from a BPA scan at a new client, the previous ICT consultant forgot to demote the old 2003 server. This server has been reinstalled at the mean time. I also see errors & warnings in update service that is trying to apply updates to this old non existant server anymore.
What is best practice to remove this server from the 2008 domain? Just remove it from AD users & computers + sites & services? Or is there more that's need to be done.