[Ykes]

I am new to this forum and from Denmark and hope you can help me with this problem.

I have exported a epub book from pages on iMac. Then I added a cover image in calibre, so the first page in ibooks would be a copy of the cover art. It worked fine on the iPad, but when i tried to upload this new file to iTunes, i got this problem:

Package Summary:

1 package(s) were not uploaded because they had problems:
/Users/MayComputer/Documents/Bog udgivelser/Andreas_1900.itmsp - Error Messages:
Apple's web service operation was not successful
Unable to authenticate the package: Andreas_1900.itmsp
ERROR ITMS-9000: "Andreas-1900-1920-v2-Arne_May-1.epub: OPS/toc.xhtml(10): element "nav" not allowed anywhere; expected the element end-tag, text or element "a", "abbr", "acronym", "address", "applet", "b", "bdo", "big", "blockquote", "br", "cite", "code", "del", "dfn", "div", "dl", "em", "h1", "h2", "h3", "h4", "h5", "h6", "hr", "i", "iframe", "img", "ins", "kbd", "map", "noscript", "ns:svg", "object", "ol", "p", "pre", "q", "samp", "script", "small", "span", "strong", "sub", "sup", "table", "tt", "ul" or "var" (with xmlns:ns="http://www.w3.org/2000/svg"). This error occurs 2 times." at Book (MZItmspBookPackage)

Can anybody tell me what this means.
I am not good at HTML coding.