- Check that you're adding the external runtime correctly by choosing the actual runtime folder, not the parent.
- Check that you have set Poser to show ALL libraries, because it may be set to show only one
- Check the LibraryPrefs.xml file to see what Poser thinks your library choices are. This file can be edited manually if need be (but make a backup first!)
Free stuff @ https://poser.cobrablade.net/