iBooks Author is saying my book is incomplete, how can I change this?

Hi,

I had uploaded my book onto iTunes connect and four days later I got an email back from Apple (thank you for such a quick repsonse) saying that my table of contents is "incomplete" and "inaccurate". I was wondering how I could enhace my EPUB's spine enough to get it onto the iBookstore?

Any other tips? I really want to get my book on the iBookstore as soon it is possible!!

Regards,

Sabrina