Need help woth the Syphon Filter demo

I've tried numerous times to get this to work on my PSP. After pasting the folder into the GAME directory on my PSP, I go to the little memory stick icon and try to play it. No image of the game appears, but a little box that says corrupted data. When I try to open it, it reads "This game cannot be started. The data is corrupted." What should I do? Thanks in advance.