GUID partition on a PPC mac for Leopard...

Hello All.

I already learned lots here just by reading, but now have a problem.

I seem to have an issue with my attempt at installing Leopard. I have a Macbook and I thought I found a way to install the OS disks that came with it to my PPC G4 by using the G4 as an external HDD thru the firewire target mode.
I had to repartition the HD to GUID and I was able to get Leopard on there.
But when I booted the G4 up I got the flashing finder folder. Did some more research and found out I need and Apple partition with the PPC mac and could use a program called iPartition to switch from a GUID to an Apple partition and keep Leopard.

Ok got that far. Now Leopard appears on my screen. But I can't install anything, no updates automatically or manually. I can't even install firefox because of an unsupported architecture message.
Is there anything I can do to fix and keep Leopard, or should I just go reinstall Tiger. I have heard of leopard working with PPC macs so what gives? Do I need a universal install disk?
Does universal have to do with the GUID vs Apple partition?