The description of the function FcDirScan states: "Scans an entire directory and adds all fonts found to set". But scanning the given directory the function FcDirScan adds 0 fonts, while there are 2 fonts in this directory.
The detailed bug description with that folder archive file to download can be found at:
Created attachment 12223 [details]
The folder with fonts
*** This bug has been marked as a duplicate of bug 12949 ***