As you can see on the official web page, Adobe Premiere CS3 is compatible only with Windows XP and Windows Vista platforms. However, in order to install the software, you can try the Compatibility Mode. Right-click on the installation package, select Properties and go to the Compatibility tab. Check the Run this program in compatibility mode for box and select Windows XP or Windows Vista from the drop-down list. Click Apply and then OK. After that, right-click again on the installer and select Run as Administrator option. If it doesn't work, you will need to upgrade the software.