Folder management isn't just a case of how Poser does it. If you go through the "view" tab in the drop down menus of where your folders are then you will see another side menu saying "arrange icons by" and then that gives you other options like "type, size, name etc." Tick whichever of these you want to display your sub folders or folders in. Bobbie Boucher is right also, a slight change like upper or lower case or a letter in the wrong place will make a difference.

Injustice will be avenged.
Cofiwch Dryweryn.