Upgrading to Poser 5 is one option - apart from PBooost, that's the only way to create sub-folders. P4 won't recognise them. What I do is to create a 'storage' folder outside of the Poser library, and move stuff into and out of there. It sounds as if you've tried that without success, but rest assured it can be made to work. A couple of tips - use P3dO Explorer to move the library items, because that will move the thumbnail with it. Second, don't move anything from the DAZ injection poses, because this can break your character packages. You can also, in addition to this, move some or all of your poses to the camera library. Change the extension from PZ2 to CM2 and they'll work just the same.