Emulating metal gear solid on duckstation

I downloaded the PlayStation bios files with the 3 scph55.. files and imported them to duckstation, i then give permission to control files in the PlayStation bios just in case that was a problem, and permison in the download directory, i select the metal gear solid file(which i downloaded from this site) and it said " failed to load cd image", idk what to do or how to fix this, pls help