You’re running the BeOS on a PowerMac, and you can’t find your SCSI CD-rom drive with any regularity. First, rename your CD-driver extension (should be „Apple DVD/CD“ in System Folder:Extensions) to “ Apple DVD/CD“ — make sure the space is in there.
Reboot into BeOS, with an audio CD in the player, and check to see if the disc comes up in the CD Player.
If that didn’t work, check your SCSI chain. Disconnect everything off the SCSI chain (the fact that it works fine under MacOS isn’t any indication that it’s okay with BeOS) and try booting again.
This is what tricked me – I have an IDE hard drive in my PMac, and the hard drive appeared in the boot selection window every time, but the CD never showed up. When I disconnected both my Zip drive (internal, wasn’t that fun?) and my scanner, it all worked. Be especially sure, especially when you’re dealing with external terminators, that they work well.