Thought I'd share this gotcha and the fix I hit today.
VMWare server version 2 is a pretty big MSI and as I found can result in a GPO security policy error (ie: not allowed to installed because of the policy).
The fix is this:
FIX: Error message when you try to install a large Windows Installer package or a large Windows Installer patch package in Windows Server 2003 or in Windows XP: "Error 1718. File was rejected by digital signature policy"

