You should probably follow this guide now: http://sgwindowsgroup.org/blogs/panda/archive/2010/02/01/prepare-a-windows-2000-forest-schema-for-a-domain-controller-that-runs-windows-server-2008-r2.aspx
To prepare a domain for Windows Server 2008 or Windows Server 2008 R2 0. Raise the domain functional level to native mode (via ADUAC -> RC domain -> "Raise Domain Functional Level" -> (pick the one you need if you still run 2000). 1. Identify the domain infrastructure operations master (also known as flexible single master operations or FSMO) role holder as follows: * In the Active Directory Users and Computers snap-in, right-click the domain object, click Operations Masters, and then click Infrastructure. 2. Log on to the infrastructure master as a member of the Domain Admins group. 3. Insert the Windows Server 2008 or Windows Server 2008 R2 DVD into the CD or DVD drive. 4. Click Start, click All Programs, click Accessories, right click Command prompt, and then click Run as administrator. 5. If you are using the Windows Server 2008 DVD, type the following command, and then press ENTER: D:\sources\adprep\adprep /domainprep /gpprep Where D: is the drive letter of your CD or DVD drive. If you are using the Windows Server 2008 R2 DVD, type the following command, and then press ENTER: ImportantImportant Windows Server 2008 R2 includes 32-bit and 64-bit versions of Adprep.exe. The 64-bit version runs by default. If you want to run one of the Adprep.exe commands on a 32-bit computer, use the 32-bit version of Adprep.exe (Adprep32.exe). D:\support\adprep\adprep /domainprep /gpprep 6. Allow the operation to complete, and then allow the changes to replicate throughout the forest before you install a domain controller that runs Windows Server 2008 or Windows Server 2008 R2.