[The 13th Ghost]

Okay, I'm new here, and I'm having a problem continuing Final Mix +. I'm currently in the area where Roxas gets the keyblade again(the area Twilight Thorn resides in) and the screen goes grey. How do I fix this problem? Also, I'm still new to the PSXC2 like a lot of people, but I don't usually understand the computer part of it, so if you get fustrated with me, forgive me.