Make sure you install the Kontakt/Kompakt/Intakt Player stuff as normal, and make sure to run the standalone application of the library once (this completes the registration process). After that, you can use them in K2 freely.
kontakt 2 can play kontakt player 2 libraries. I actually just released mine today. Ambience Impacts Rhythms is the first kontakt player 2 library out the gate! Which I am really excited about. The nice thing about loading the instruments into kontakt 2 is you get mroe control and can unlock the instruments so you can play with the scripting language, skins and modify and save instruments to your liking