Great. I had to use Terminal to enter the hidden folder .image into the cd then type "open iDVD1.dmg" to start the installer. Now it never crashes on the G5 while the iLife version always froze the system. An encoding error at some point but I found the solution in Apple discussion forum about iDVD: importing from "File" menu the iMovie movie (not self contained, not dragged or exported directly from iMovie) and then create and burn the iDVD project.
Thanx
Sam