Booting from LiveCD

Anyone have any ideas on this problem? I've googled all weekend and
gotten no closer to a solution. I am not generally a Linux or Mac
person, but nor am I entirely unfamiliar with both.

I have an older G4 MacMini. It's a 1.5Ghz PowerPC G4, upgraded to 1GB

My goal is to put Linux on this little machine, ultimately to use as a
file-server. My problem is that I can't get any of the LiveCDs to
actually boot.

I've tried downloading the PPC-port of Ubuntu (both v6.06 and v8.04),
as well as YellowDog v6.1 PPC. I've burnt the ISOs to CD (or DVD, in
the case of Yellowdog). I insert the disk into the drive, restart the
Mac holding down the "C" key... and nothing. I get bumped into OSX.

Not giving up, I restart holding down the CMD-OPT-SHIFT-DEL key and
get a selection of two buttons (one for OSX, one for Linux); this
doesn't work either. I get the graphical menu but clicking on the
LinuxCD icon doesn't start the installation.

If I insert the OSX install disc, I can boot from that and, =while in
OSX- the drive can *read* the Linux CDs; this would seem to indicate
that the hardware is working and its not an incompatibility issue with
my discs.

DiskUtility report the burnt CDs as *not* being bootable. But why? I
tried burning the ISOs to disc on the Mac, and burnt another from a
PC; the discs just are not bootable. I'm just downloading the ISOs and
burning them to CD; nothing fancy. All indications are that these are

Any ideas of where I should go from here?

ISOs used: