You missed Pa+La+U = Palau. Had you used that for Oceania, you wouldn't have needed the double Iodine for Kiribati, but you'd also have to redo the quiz. It's not good for a valid answer to not be accepted, so I think you should redo the quiz. You should select your letters carefully so that there's only one correct answer per continent.
Sumguy: Thanks for the feedback. I won't redo the whole quiz but I will add an annotation.