It's not a bug in the program, it looks like one step got missed in the manual ... the most likely reason for the "fail" is that there was no "Runtime" folder beneath the folder you selected.  So ... let's say you want to create a library folder to install all your Miki 3 content into.

You can get it to work as follows:

1. Open the Library palette if it is not open.

2. Click the Add Library button (+) to open a standard Browse for Folder dialog box.

3. Select the hard drive that will store the new Library files you want to add (for example, you can choose your D: drive)

4. When the Browse for Folder dialog appears, click the Make New Folder button. You will be prompted to enter a name for the new folder. Enter the name of the library as you would like it to appear at the top level (such as Miki 3).

5. With the new Miki 3 folder selected, click the Make New Folder button again. Create a second new folder named Runtime beneath the first folder you created.*

So the file structure now looks like this:

D:
     Miki 3
          Runtime

6. Go back and select the  Miki 3 folder. Then click OK to create the new Library. Poser will add subfolders for each Library palette category (Figures, Props, etc.) beneath your selected Runtime folder. You may then populate this new Library at will.

 

Hope this clarifies. Manual will be updated.