Why can't I instal Leopard on my PowerBook G4?

Here’s the thing, I have installed Leopard on my PowerBook G4, but I installed an update, 10.5.2, which killed my computer and started making it Kernel Panic. I re-installed Leopard, but when I went to install it, I got an error message repeatedly that said “Could not install some files in Volumes/Macintosh HD”. The weirdest thing is that I can still install Tiger and everything works fine, and I know Leopard works fine on my machine, so what’s going on!