Attached Link: Linking Your P4 Runtime in P5

You just link your Poser 4 runtime to Poser 5, tutorial at the link above. You don't have to move any geometries or textures, but I'd strongly suggest that you run CorrectReference on your P4 libraries to get rid of pathnames that reference specific directories and hard drives. P5 is very literal when it comes to looking for textures and geometries and if the pathname says that the geo/tex is in D:mystuff, then it had better be there. CorrectReference is in freestuff.