Okay, with the Roudolph patchers, the .BAK is the game, UNPATCHED. You need to use the .NDS file not the .BAK. I am playing the game with no problems (so far) saving/loading all ok.
I'm going to play this game now.
A big thank you to Roudolph for creating the patch for this awesome game, also a thank you to [C2] for releasing this dump to the net. I also can't forget SQUARE ENIX and V Comix colab that created this great game. (Of whom I'm steeling from?) Thank you all, I am going to enjoy this game. I will hopefully make a review of the game soon.
Might I sugest an open translation of this game? I'd at least like the menus to be translated, I don't want to accidentally erase my save. X_X