JSI Tip 9327. The Windows Server 2003 Service Pack 1 Administration Tools Pack.

When you install SP1 on your Windows Server 2003 computers, you should remember to uninstall any previous Adminpak.msi from Windows XP workstations that you use to manage the domain, and install the new Adminpak.msi, which you can also get from the Microsoft Download Center.

NOTE: See Which Adminpak.msi file should I use?

The Microsoft Download Center Windows Server 2003 Service Pack 1 Administration Tools Pack page contains the following description:

The Windows Server 2003 Service Pack 1 Administration Tools Pack (adminpak.msi) provides server management tools that allow administrators to remotely manage computers running Windows 2000 Server and Windows Server 2003 family operating systems. This is the Service Pack 1 version (build 5.2.3790.1830) of the adminpak.msi file.