I really don't get that statement as well.
If it was received by some supernatural source, from an all powerful and all knowing being... Why would it feel bound to use newly generated paper. If it was all knowing, it would create the book outside of space time, when it felt making it a book it would.
That is the problem trying to compare Science with the Supernatural. If you have an effect said to be created from a source that cannot be measured so, your attempt to measure probably will not come with good results.
Now if you look at the article in terms of more of a scientific point of view other than a way to bash a religion. But the fact that they probably used an old empty book create it, or the fact the much if Islam is from Christianity and Jewish religions as well, you may expect it was parts to be already written.