Socom 2 locks at level 5

Every time I beat level 4 on SOCOM 2 and hit continue it just sits there with the spinning disc image forever. I tried replaying from the begining, I bought a NEW SOCOM 2 disk; I've probably played levels 1-4 20 different times completing them different ways each time, and nothing worked. Sony has no answer for me other than it's a bug that can't be fixed. Can anyone help!?

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