Why do Final pantasiya IV The After Years corrupt all saves?

Whenever I play my Final pantasiya IV The Complete Collection to my PSP and I play Final pantasiya IV and Final pantasiya IV ~Interlude~ it works fine.But whenever I play Final pantasiya IV The After Years and advance a little at Ceodore's Tale all my save data corrupt.Do you know if it has a problem or something because it's really annoying.