A few users on Windows Vista have been having trouble installing ProClarity Desktop Professional. The users are prompted to update Microsoft Windows Installer to version 3.1 v2, reboot, and then they see the request to update the Installer again.
The workaround is simple, just run Setup.exe from InstallationPackLocation \Desktop Install\Install
For more information, please see this Microsoft KB article: http://support.microsoft.com/kb/934072. It's unknown if this is an issue on the new Windows 7 beta - but, we'll be on the lookout for this issue on current and future Windows 7 releases. (On a side note, I love Windows 7 - nice work Windows team!)
Thank you TJ for letting us know this item needed extra attention!