You NEED to authenticate a DVD ORIGINAL, BEFORE (or while, I'll get to that) you load your player, or you need to build a PS2 DVD MASTERDISC, that loads your player, with your divxx on it, with the cd-dvd-gen, and launch it with your dvd swap magic disc (Delta-9's right about this). If that's beyond you, I'd DVD double-swap from ulaunchelf, authenticate a dvd original, and swap in the dvd-r with your divxx (however you load a dvd-r, now) then run your player from ulaunchelf.
I havent done this in years, but I HAVE DONE IT, it is absolutely possible, and this will allow you to play mp3's from a dvd, too, if you want to.
A toxic agent on a dangerous mission so secret, even I don't know what it is, because if I did, I would have to kill myself. I don't even know who's side I am on.