Hmm... Windows Server 2003 and Windows Vista. If you have stumbled upon issues while trying to administer Windows Server 2003 from Windows Vista, then read on: you will be provided with a solution. If not... well it won't hurt, I promise.
The issue I was referring to is an error message when you install the Windows Server 2003 management tools on a Windows Vista-based computer: "MMC could not create the snap-in." This - of course - prevented Windows Server system administration from Windows Vista via the Windows Server 2003 adminpak.

Microsoft delivered an official Knowledge Base article addressing the issue. "As an administrator, you can use the Microsoft Windows Server 2003 Administration Tools Pack to install the Windows Server 2003 management tools on a Windows Vista-based computer. The Windows Server 2003 management tools provide remote server management functions. This article describes some of the limitations that exist when you run the Service Pack 1 (SP1) version (build 5.2.3790.1830) of the Adminpak.msi file on a Windows Vista-based computer," reads the summary of the KB article.

The Microsoft Knowledge Base article for the installation of the Admin Pack on Windows Vista describes the issues related to the Windows Server 2003 management tools on the operating system, the symptoms associated with the issue, the limitations and delivers a resolution to resolve the problems.

The installation of the Windows Server 2003 management tools on Vista produces "error messages and many of the administration tools seem to be missing or are not properly configured. Some of these issues are related to User Account Control and not having the necessary administrative privileges when attempting to install the pack. Note that this does not address managing Windows Server "Longhorn" from a client machine (either Windows XP or Windows Vista). We are working on a new version of the Admin Pack for Windows Server "Longhorn" and we will provide an update on our progress with this in the Beta 3 timeframe," explained a representative of the Windows Server Division Team.