Using the Asus Xtion Pro Live camera with Personify is easy.
First, DON'T install the drivers from any CD that came with the camera.
Personify Live is a self contained installer that will install all the requisite drivers as long as you have the camera connected to the PC.
Note that the installer will automatically detect the camera and install Personify Live and pop up a dialog about installing drivers from Primesense. NOTE: If you don't see this pop-up, your installation is INCOMPLETE.
Once you accept the dialogs, you can double click on the Personify Live icon and use it with the Asus XTion Pro Live. You're done (except on certain Windows machines, where Personify Live may prompt a reboot when you first launch it)