Windows 2008 shipped recently, and I've been updating my field kit with all of the various installation media and supplemental programs needed for client site deployments.

One issue I ran into is when installing the Books Online standalone package on my Vista x64 laptop:

"This installation package cannot be installed by the Windows Installer service.  You must install a Windows service pack that contains a newer version of the Windows Installer service."

The message is pretty self-explanatory, but it was strange that at this time Windows Update indicates my computer is all up-to-date. 

To resolve this issue I needed to manually download the update to Windows Installer 4.5, apply it, and reboot. Then installing the updated install package proceeded normally.