We've created this Forum Thread with some workarounds and advice to assist you in publishing you ebook.
After studying very closely and viewing the video tutorial and following the forums here, my ebook has failed and I get the message 'there appears to be no toc.' Here's what I did based on all the info I've gleaned in recent weeks:
1. Copied and pasted my doc into notepad (to wipe out any default headers etc.) and copied into a new word doc.
2. Applied heading one style to title, copyright line, chapters.
3. Used soft returns (as suggested by video tutorial) so that the title doesn't appear at the very top of the page.
4. Used 3 soft returns before each chapter number (for the same reason as above)
5. Used garamond font throughout 14 size for all text except copyright page (size 12)
6. I did some editing to re-establish italicised words that notepad altered (very important for understanding the story)
7. Formatted the heading style from the default calibre to garamond to match the rest of the text and chapter numbers in italics and bold.
When this failed I tried applying heading 1 to title and copyright line and heading 2 to chapter numbers. Still same message.
The message also says that some 'other' things have been fixed, such as unsupported fonts. I've used garamond throughout.