I downloaded NGS02 demo few days before, but when I put my NGS01 into the PS3 today, it shows an error message: The copyright protection information is invalid(80029513), anybody know what happened, I suspect all NGS01 are not able to run now, please help!

just like what Lord Doku suggested.

Delete the demo.

but I say, go to the Save data and Game files and delete the save settings for NGS2 demo.