As you may know, DAZ content files come predominantly in 2 flavors, 1 file for DS and the other for Poser.  However, both zip files contain a primary or first level, folder called Content.  All the different subfolders are nested within this primary folder.  The problem arises when you manually unzip the contents, you add this Content folder to your DAZ or Poser Library.  DS and Poser do not recognize the Content folder and it shouldn't be there by default.  If you are doing a manual installation, you need to go down 1 folder level and extract all the subfolders to your library.  The images below show what you need to install from the zip files.

                                                                               

                                                                             

DAZ has packaged its content differently than your conventional Renderosity zip file and it is because DAZ wants you to use its Daz Install Manager program to organize and add content to each of your programs easily.  The program is designed to strip away the Content folder and install the underlying subfolders in their right places.  This explains why, when you perform the manual procedure, you don't see the content in the Poser Library.