> I hold "C" and boot from CD, get the language and keyboard choice, directly after
> that I get the message "MorphOS boot.img is too old , in order to boot from
> MorphOS CD type boot/pci/cd to the OpenFirmware prompt."
> Hard to know what does that mean for a novice?

I'd say this means that booting from CD fails for whatever reason so that OpenFirmware defaults to loading the boot.img from your hard drive instead. The magic key combination for entering OpenFirmware is CMD+OPT+O+F. Hold them concurrently when booting and do as the error message says.
And btw, if you downloaded the MorphOS 3.2 ISO during the initial 4 hours, you should re-download it. There was an error that made booting the CD impossible on Mac.