Since no one replied to you I will try to give you some help. I can't say about your particular error but if you want to install from the CD-ROM on an "Old World" mac you have have some floppy.
These are exert taken from Debian install manual:
5.7 CD-ROM
CD-ROM booting is one of the easiest ways to install. Currently, only PReP and New World PowerMac systems can boot from a Debian GNU/Linux install CD. If you're unlucky and the kernel on the CD-ROM doesn't work for you, you'll have to fall back to another technique.
Installing from CD-ROM is described in Booting and/or Installing from a CD-ROM, Section 6.4.
6.4 Booting and/or Installing from a CD-ROM
If you have a CD which is bootable, and if your architecture and system supports booting from a CD-ROM, you don't need any floppies. Often, it's as simple as puting the CD-ROM in the CD drive and booting. Currently, the only PowerPC subarchitectures that support CD-ROM booting are PReP and New World PowerMacs.
Even if you cannot boot from CD-ROM, you can install the base Debian system from CD-ROM. Simply boot using a different media, such as floppies. When it is time to install the base system and any additional packages, point the installation system at the CD-ROM drive as described in ``Install the Base System'', Section 7.15.
Your mac is an "Old World" mac. That is why I opted to install Yellow Dog on my computer because of the ease of installation. I'm temped to jump back to Debian once I get a better grip on things. But Yellow dog had the BootX integrated into their install CD so I thought that would make it easier than trying to figure out BootX by myself and mess with the floppy also. Another thing I read somewhere that there might be issues with Performas. Isn't yours a Performa. But I did not obsorb the info because it was a non-issue for me. I just installed YDL on a Power Computing Power Center 132.
I hope this helps a little.