Ps3 error can't sign in to smothers user's sign in ID?

Okay so I made a PSN Account with PlayStation Plus on it on my PSP, and I now have a PS3 and my PSP broke, so I try to sign in and it says "cannot sign into another user's sign in ID" and I don't want to make a new account because I have Playstation Plus and then I can get the free games because of the PS3 hackings.