Here are a few links to informative articles about Windows Installer problems.

Windows Installer Team Blog : "Stop Installation Idiocy" PCWorld's Hassle Free PC article:
http://blogs.msdn.com/windows_installer_team/archive/2005/11/01/486587.aspx

Frequently Asked Questions About Windows Installer:
http://www.microsoft.com/windows2000/community/centers/management/msi_faq.mspx

Installation-On-Demand:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/msi/setup/installation_on_demand.asp