I recognize it's a pain. Unfortunately Apple shipped those DVDs with a buggy Disk Utility, as you've seen. Since most users write directly to the backup drive (as we recommend), you'd normally be able to start up from the backup, which is much easier, of course.
Note that there's a workaround in the comments of
this blog post, too, but involves using the Terminal.
Anyway, if you do have another Mac, you'll boot that Mac normally. Then, put the Intel mac into FireWire Target Disk Mode, connect it to the other Mac, mount the image and use SD! to restore. Should work just fine...