areyou setting your layerbreak at 1913760? probably, just in case.
I am hitachi 47DJ, with FW 2.1 (too lazy too upgrade

). I personally use XBCr/sh-d162C ,and burn using IMGburn using the .iso file and layerbreak set manually (i do not like using the .dvd file). Always on verbatim at 2.4 or 4X with booktype at DVD-ROM.
Do you have friend were you could bring your original and corresponding backup to test if they are OK. If so you would know the problem is not the backup.
rgds,soso