From the release notes for Windows Server 2003 Service Pack 2. http://technet2.microsoft.com/WindowsServer/en/library/ed5382af-e819-4d33-ace0-225d31b7ab751033.mspx?mfr=true
If you are running the initial version of Active Directory Application Mode (ADAM) that was available as a download, you will not be able to directly update the computer to Windows Server 2003 Service Pack 2 (SP2). If you do so, the ADAM instances may stop functioning.
Preventing the issue
To prevent this, do one of the following before you update the computer to Windows Server 2003 SP2:
Download and install Windows Server 2003 Active Directory Application Mode Service Pack 1 (ADAM SP1). Follow the instructions provided in Microsoft Knowledge Base article 902838 - http://go.microsoft.com/fwlink/?LinkId=82253 . Then, install Windows Server 2003 SP2.
If you have the first release of Windows Server 2003 R2, then update ADAM as follows. (Disc 1 contains SP1. If the product discs that you have do not specify which service pack is included, then the discs contain SP1.)
Install both disks.
Update the ADAM instances by installing ADAM using Add/Remove Windows Components in Add or Remove Programs in Control PanelInstall Windows Server 2003 SP2.
Correcting the issue:
If you have already installed Windows Server 2003 SP2 (for example, from Windows Update or by using Update.exe) without first updating ADAM, you can correct this issue with the following procedure:
1. Uninstall Windows Server 2003 SP2.
2. Download and install ADAM SP1 by following the instructions provided in Microsoft Knowledge Base article 902838 - http://go.microsoft.com/fwlink/?LinkID=82253 .
3. Reinstall Windows Server 2003 SP2.
For more information about the options for upgrading to the second release of Windows Server 2003 R2, see the upgrade diagram in Upgrading When You Have the SP2 Version of Windows Server 2003 R2 - http://go.microsoft.com/fwlink/?LinkId=85407.