What are they and how do I use them?

I'm a noobie to Poser, so I'm still learning.,

Everytime I clicked on a INJ in the pose directory of the libraray the computer gets busy  and unresponsive for several minutes, then I'm asked to look for a delta file. After finding it, the computer does the same thing, and asks for another delta, and so on and so on. And it seems to happen with any INJ I use, wether from here or DAZ..... Am I doing something worng?