You all get poisoned so you need to cure the poison.
Set someone as White, and rank it up to 3, then unlock white magic level 1, which includs Cure Poison.
Hold down the button when you cast to "charge" it and make the cure radius bigger, so you can cure everyone in your party at once.
Does that make sense?
I have a white magic with a skill of 11, the charachter is level 17.... no cure poison skill.
Not sure what the deal is, I mainly trained him as a barrier user...
