A few people wrote me that they had trouble buying the book on the Lulu site around 3-4pm Eastern. Apparently someone at Lulu was concerned about copyright issues, and the book was unavailable for a very short time. It is now back available for purchase.
In case anyone's wondering, the copyright law allows for what's called "fair use" or "fair dealing," whereby a book can quote small parts of another book as long as they're short and as long as the quoted parts are a small part of the new book. This is clearly true of Harry Potter and Torah. I also did not use the Harry Potter distinctive lettering on my cover, to avoid infringement issues.
Anyone can add a comment to this blog message if there are any more problems. But from my checking, the book is back available on the Lulu site for purchase and preview.