I installed an “older” msi (QuickCode.net for vs.net 2005) on my vista box, tonight, and it apparently runs a custom action to register an assembly that Vista doesn’t like so much.  That custom action requires elevated priviledges and the install will bomb if you try to run it under a typical user account.  So… I created a batch file that calls msiexec.  You can run the batch file as an administrator and everything installs as it should.  I copied the msi to a temp directory (C:temp) and created the batch file as follows:

msiexec /i c:tempQuickCodeSetup2005.msi

Then all you have to do is right-click the batch file and select “Run as administrator”