Weird. The !DAZ folder should be there in Libraries (though you won't see it from inside Poser).

If you're using Poser 5, you should be able to rearrange your files, as long as you keep them in the right section of the library. Figures in figures, Poses in Poses, etc.

I've moved all the DAZ !INJ files into their own folder, because I hardly ever use them. I also have all the character INJ and MAT poses in their own folder, all the actual poses in their own folder, a separate folder for Morphing Fantasy Dress MAT poses, because I have so many of them, etc.