Before Windows Vista, programs could store their data in their c:/Program Files/Whatever folder. Vista changed that, so now they have to store the Runtime elsewhere. This helps to prevent the program from being broken by changes to the data.

Older DAZ installers check to see that a Poser.exe is in the parent directory to make sure you're installing in the right place. Victoria 4 is older. If you tell the installer that it's a DAZ Studio install it will not make that check.