10.4 to 10.5 upgrade problem

Im running 10.4 on my ppc g5 tower and i was trying to upgrade to 10.5 i did the install but now i get this screen. but i try to put in the info and it doesn't work. this is as far as i can go i cant even boot from the disc. also i was just doing and update not a clean install to avoid having to redo all my applications. help........