Tiger problem will Leopard have the same issue?

I have a G5 with 10.3 and recently bought Ilife 08 and found that I needed to upgrade my OS to Tiger or Leopard. I was contemplating purchsing Leopard when a friend loaned me a Tiger Disc.
But I have had no luck installing Tiger. On the simple install the machine's fans blow at max speed for over 45 minutes with nothing happening. In the custom install after about 15 minutes I get a Missing Bill of Materials error message.
On the regular install after a while it may come to a text screeen asking to boot-mac or shut-down. It also says some memory is missing
Yes I know I should buy a new copy of Leopard but will I have the same problem. Among some things I've tried is disconnecting all external USB and Firewire devices.
My CPU is a single processor G5 1.8 with 1 gig of Ram

is the tiger disc a retail copy or a restore copy from another machine, either way working with that disc is still illegal and you should not install it on your machine, or discuss getting it to work on these forums.

I will get a legal copy if it will work...

I plan to purchase a legal copy of Leopard but I want to know is this just going to be another problem. My purchase of Iilfe 08 was to use it's web design software. If I have to face lots of battles trying to get a new OS installed then I think I should just go buy a copy of Dreamweaver that I know will run with 10.3. If Leopard does not have these problems then I will buy it.