Help get this topic noticed by sharing it on Twitter, Facebook, or email.
I have forwarded your question on to our Book Tech staff, so they can help you find a solution. If you ever have any questions or issues with the content of a title, you can also contact them directly at email@example.com or call them at:
1-707-827-7019 (outside the USA)
7:30 am to 5:00 PS
Customer Service Representative
Have you tried re-downloading the epub file? I was able to open that ePub in Adobe Digital Editions and also on my iPhone in iBooks.
Also, was it iBooks that said "wrong format" or the browser that you downloaded it in?
O'Reilly Book Support