Ive been using that same location Black Mage, the forest south of Gaia after having walked the required steps and after a few hours still no luck?

Man this is getting annoying...

I also heard that some monster become extinct in the japanese version after you have the last spell, which i have...

So maybe they are all gone? Besides i read you can still get all the extras with only 97% of the monsters, so i might do that...