If the zip file is properly created, there should be a runtime folder within.  Just unzip it to your Poser 7 folder directly, everything else should go where it is suppose to go.  DO NOT unzip into the runtime folder! 

Take the time to open your zip file and familiarize yourself with the content hierarchy which should be the same in your Poser runtime folder.  This will give you some idea how files are placed within folders making it easy to locate them when you are actually in the Poser app.  Many individuals like to unzip their files separately from the Poser folder, edit the content of the fresh runtime folder, then manually transfer each folder to the proper place.