Is your CD scratched or something? Also , i think it's the firmware you have...i guess you have to wait for the future, and about the saves...you can find one in this link : http://www.gamefaqs.com/console/psx/save/197909.html
Playstation does that sometimes...I dont know why, but it happened to me with kh1 and ratchet and clank. And it always happens to me at the kh2 ending on my ps2. You might have too much memory on your card. Sometimes the laser overheats or a disc scratches when you use/play it too much...If its only for MGS, it might be the latter. Thats all I've got for now.
