Batman: Arkham Asylum collector's edition are going a bit batty on the game's official forum due to seemingly botched DLC codes. The codes, included only with the CE, enable two challenge map downloads -- but, so far, have only unlocked ire.
Not to fear, as Eidos community reps are asking for the spurned downloaders' codes so that they can be "passed on and investigated." The publisher is definitely on the case, although there's no clear ETA for a fix. We suggest bookmarking the thread if you're having problems, as it seems to be a source of frequent updates. We also suggest that you don't think of doing anything crazy with that replica Batarang. They're just DLC codes, folks. It'll be OK.