I reread your post with the screencaps and you mention that you have followed Steve Harms' tutorials so you have some familiarity with the common Poser terminology.  Tell me how you obtained the additional content you wish to install and how you installed them.  No matter how trivial this may sound, newbies always manage to either overlook a particular step or are unfamiliar with how to decompress Poser-ready files.  That is why it is so important to convey as much information as you can remember to make it easier for us to determine the correct approach.  I don't want to overwhelm you to the point of giving up, you are genuinely interested in pursuing Poser, so let us help.