Ps3 – “You did not create this game data. File cannot be loaded” error message

I got a used PS3 from a friend and started playing under an an account just named 'user'. I didn't think anything of it. I never connected to the Internet or anything. I'm not really an online player of anything. I'm about 50% through the game and I wanted to invest on the BAWSAQ. So I created a PlayStation network account from my phone. Then I hooked up the Internet and tried to sign in. But apparently someone had already used this account with a different login. So I created a new account on the PS3 and copied my most recent save over.

Now I am getting the error message: "You did not create this save game data. File cannot be loaded." How do I fix this? I don't want to start over and I don't want to miss out on the money for the 3rd stock market investment for the 3rd and later assassinations. I would appreciate any help. This is my first time ever playing on a PlayStation. I usually play PC games. I have enough knowledge that if I need to edit the save game file on my my computer I can but I'm not sure what to change.