You can't install Email Address Pro on Windows 8.1 64bit because it hasn't been developed/updated to support this operating system.
I've downloaded the installation package and found out that it's compatible only with Windows 95, Windows 98, and Windows NT version.
When you try to install it, an error appears saying this file wasn't build for this version of Windows (7, 8, 10).
You either install Windows XP using a virtualized way or as a dedicated install while wiping the current version of Windows on your PC.