this is a prob with your ps2 +r medias are not compatible v3 - v8 they are only compatible with version 9 and higher (SCPH 50004 and higher).
i think the ps2 reads also the media type and not only the booktype.
if the ps2 would only read the booktype we would be able to play backups on unmodified ps2 when set the disk to dvd-rom, but this doesnÂ´t work.
or iÂ´m wrong???????????