Im using OS3.1
Remember asim uses the cd0: icon in storage not in devs/dos drivers.
check storage/dosdrivers/cd0(or whatever its named) for the right device number.. if you picked CD0 in the asim install, it sets unit number to 0.. if you select cd2 its 2,etc. remove any cd0 or anything from devs:dosdrivers.
is the scsi cd drive known to be a working drive?
some old scsi cdroms had very buggy firmwares but i suspect its not that.
when testing use a pressed cd,not a copy you made,again some buggy firmwares in drives dont like some burned cd's