Thanks for the hints, guys.
I finally solved this issue.
I've thought that with a fresh OS 3.9 installation I never had a similar problem so I copied DEVS:CD2 , L:AllegroCDFS and L:CDFileSystem from an old, clean OS 3.9 Installation in my DEVS: and L: folders and now the name of files are shown correctly.
That solved also another issue that was that audio CDs weren't automatically mounted when I inserted the CD but I had to open "songplayer" and click on cdrom icon.
Probably one of those files was corrupted or a version not compatible with the system or the hardware.