Gothwillowfan, I found a solution, there was a post over at Content Paradise about this. I did the same thing they did and it worked but I've never had to do it this way before and I haven't seen it described clearly in the documentation.

As an example , if you wanted a runtime to hold all your toon related content, you set it up this way: Create a folder named Toons. Within that folder create a folder named Runtime. Within that folder create a folder named Libraries. Then populate the Libraries folder with your content folders, character, pose, hair, etc. which contain your various toon content. Click the + (add runtime and choose the folder you named Toons to mount the runtime.

Funny thing is I didn't have to do this to add my old Poser 6 and Poser 7 runtimes.