The correct setting for the layer break on the PAL DVD-9 is cell 27 which is right after Tarkin says "Terminate her, immediately". The NTSC DVD-9 also had this layer break set but some versions of IMGBurn reported it as a bad layer break position, even though i was able to burn it ok with my version of Imgburn. So there was a fix posted to solve the imgburn problem that changed the layer break for the NTSC to cell 28 which is the start of the scene that Vader walks to the falcon in the death star hangar.