There are a lot of reports of the leaked copy of Arkham Asylum popping up with a particular error. And a peculiar one at that. Damaged Downloadable Content Errors are popping up for everyone at different points in the game. Amost always in relation to a point where Catwoman appears. There have been several fixes posted. To me this sounds like the most likely to work:
Restart the game with no profile signed in. Continue past the error where it tells you that you cannot save the game without signing in. Start a new game. Sign in shortly after the game starts and it will boot you back to the Main Menu and display somthing like “Sign in change has occurred“. Then simply choose to Continue without Catwoman
