Nruddock, I don't think that's the issue.  If you note my post above and view the OP's screencaps, the runtime folders are named incorrectly.  You can nest numerous runtime's within the primary Poser folder, as long as each runtime is contained within it's own individual folder.  We forget that there is a separate download folder within Poser that contains it's own runtime structure; we just overlook it because we don't want to overcrowd the primary with too much content.