Is anyone else having problems loading the newest version of iTunes (10.6.3) on Windows?

Is anyone having problems loading the newest version of iTunes (10.6.3) using Windows Vista? My current iTunes program version 10.6.1 keeps telling me there is an update but when I try to load it the information box goes away and nothing happens. I have tried downloading the new version from Apple web site but it brings up a warning screen of " iTunes setup.exe is not commonly downloaded and could harm your computer." I select the action of run anyway and get the next error "iTunes Setup.exe is not a valid Win32 application." What Gives?