Does the CD-ROM drive respond at all? Is it on some weird controller? Are you sure you were able to boot from CD-ROM, 'cause it sounds to me like the installer can't find the drive at all. BTW, to boot from floppy you need boot.img, not cdboot.img.
If indeed the problem is that the installer can't find your CD-ROM drive, feed it a drivers floppy (from drivers.img) and see if that fixes it.
If it did boot from CD-ROM and then gave errors, it looks like something is wrong with the CD-ROM. If you got a good iso, you got a good iso, no need to download it three times. But maybe the CDR is crappy, or your burning software has a problem w/ iso images.