EmuElec 4.6 - Cant get work CD-I

I have tried to run a CD-I game (CHD file). I copied following files into the ROM folder:

cdi490a.zip
cdi910.zip
cdibios.zip
cdimono1.zip
cdimono2.zip

When i try to run the game, the MAME logo appears and in the left upper corner an error message appears: “Fatal Error: Required files are missing…” (hard to read)

Any idea, how to solve the problem? Thanks

Perhaps you can find a solution here:

Obviously, the answer is in this message. Some of your bios files are incorrect, which one? who knows, since you provide no logs.

Also the files need to be in the roms/bios folder

More information on bios here:
Arcade (SAME_CDI) - Libretro Docs