If the earing obj was imported into Poser and saved as a Prop in the library, the obj's data was included in the pp2 file (this is called embedded geometry). You have in this file all you need to package (in addition to textures, of course). It is possible to define Props (pp2) with an external obj file (usually set somewhere in Poser's Geometries directory. This method (external geometry) is mostly used with Character files (CR2) but can also be used with props. The main reason you may want to use an external obj file is that the geometry will not get saved in scene files (pz3), so that these file keep a low filesize. Also, unless I'm mistaken, Poser will load the obj in memory and use that definition each time it's needed by a prop. With embedded geometry, the object is loaded in memory as many time as there are props using that obj (meaning higher memory need) (someone may want to correct me if I'm wrong on this).