I don't think a book would be responsible for sending someone to hell just because it doesn't point the way to heaven. I would hesitate to say any book is responsible for just a deed in any case: no book we read will ever grab us by the throat and force us to do anything. :getrdun:
However, what we read can contribute to false ideas that influence the choices we make in regards to heaven or hell. In that way, a book can influence (although not be responsible for) our choice in that area. Semantics, but still important to note.
That being said, I do not believe Narnia to be innocent on this account. The ideas presented in The Last Battle could certainly be an influence toward faulty soteriology (sorry, I couldn't resist! :frog ).