Hmm, I've only run into one situation where content was imbedded in a scene file like that and I've been using Poser since version two. At that time, the scene file folder didn't exist, but you should be able to open the scene file in Poser and select each item individually if you'd like to move them around. If everything is where you want it, you could simply add your figures and pose them as you like.

If your scene file doesn't open in Poser, try importing it instead, just as you would a prop.