After upgrading to iDVD 5, it appears I now have no previous themes ie version 3 and 4. There also doesn't appear to be any version 5 themes either. Have re-installed a couple of times to no avail. Also, as I don't have version 4 on disk (it came on my G4 laptop installed) I can't go back and re-install that. A real hassle as all my previous projects have v3 & 4 themes which version 5 can now no longer access. Anyone else had any problems?
Just look at the original installation media of your PB. Somewhere in there, there's iLife '04.