Ace Combat (X2): Joint Assault

[Giuseppe789]

Hi guys...i'm trying right now to play the game "Ace Combat Joint Assault"; it works fine (except from the sound in some parts).
But now i'm blocked in a mission between the transition from one part of it to another (i do not know how to describe it); i think some scripted scene is supposed to be there.
The PPSSPP show only a black screen and a weird lopped sound.
I have tried to randomly set the video settings at different configuartions but it looks like nothing is working...any suggestion?
with love Giuseppe