Is ther eanything that says 'Continue' and 'Cancel' on the system tray/blinking orange? Or did a 'Cancel or Allow' box come up? If not, cancel out of the installation, and open up Computer > Right click on the disc > go to Explore > and find Setup.exe. Right click it and choose 'Run as Administrator'. A box should come up that asks if you would like to continue, pick Continue. See if that works. IF it doesn't, you can always try disabling UAC altogether (Go to Control Panel > User Accounts > on the left panel, should be something about disabling UAC; Click that, and hit Continue, then you'll have to reboot).
I was able to install Office 2003 without a problem on my Vista laptop (Home Premium).