CD and DVD games need different methods of ripping, and only the CD games need the media type conversions described in that tutorial and some others like it.
For a game on DVD (like the majority of all PS2 games), the basic method is very simple.
1: Rip ISO file from original disc using "DVD Decrypter"
2: ESR-patch the ISO file using any of the valid ESR patchers
3: Burn the patched ISO to DVD-R using "ImgBurn"
No other steps are needed...!!!
And doing the other steps suitable for CD could mess things up for you with a DVD game.
"DVD Decrypter" and ImgBurn are different generations of the same program, and ImgBurn is the newer version and therefore better aware of burning needs of modern hardware and media. But in the updates some good features for generic DVD ripping were 'lost'. And that is why the older version is preferred for ISO-ripping while the newer version is preferred for burning the backup discs.
Best regards: dlanor