Question: what does it mean when it says cannot sign in using another players sign in id?
Answer: If you try use another account's email address when signing in to PlayStation™Network, you will receive the error message "You cannot sign in using another user's sign-in ID (e-mail address)." To add a new account to a PS3™ system, you need to create a new User first. Then sign in to an account or create a new one.