installing mac os 10.5 server problem

hello first of all im a new user on the board just want to say hello and thank you
in advance if anyone take time to read and/or help me.

Ok on with my problem i currently got a Power Mac G5 running mac os 10.5
with firmware at 5.1.5f2. I want to install mac os 10.5 server on it and i got the
official cd to do so. I also made sure to format my disk with the good one for a
G5.

The problem is every time i try to install it it get stuck on the little apple sign on start up and
seems to run in an endless loop.

Ive tried several way to install it including formating it using another computer before trying installation
ive also tried to use other cd in case mine was corrupted.

So here i am stuck with my problem anyone got any idea what could be the problem here?