The 'checkmark' probably only indicates that the path exists, not that the path is correct for the library.
I'm not in the studio to view the settings right now, but I believe that you've set the path too deep.
I believe that you'll want to reference the root folder of each library; i.e. ".../SL-Avatar/" not ".../SL-Avatar/Sounds/"
Also, your screenshot implies that you've used the same setting for each of the libraries.
The setting will be different and dependent upon the libraries that you've purchased and installed.