package element unique-identifier attribute does not resolve to a dc:identifier element (given reference was '') package dcterms:modified meta element must occur exactly once dcterms:modified illegal syntax (expecting: 'CCYY-MM-DDThh:mm:ssZ') @refines missing target id: '' itemref element idref attribute does not resolve to a manifest item element manifest item element fallback attribute must resolve to another manifest item (given reference was '') media overlay items must be of the 'application/smil+xml' type (given type was '') global media:duration meta element not set item media:duration meta element not set (expecting: meta property='media:duration' refines='') manifest items referenced from the handler attribute of a bindings mediaType element must be of the 'application/xhtml+xml' type (given type was '') spine element toc attribute must reference the NCX manifest item (referenced media type was '') spine element toc attribute must be set when an NCX is included in the publication Exactly one manifest item must declare the 'nav' property (number of 'nav' items: ). The manifest item representing the Navigation Document must be of the 'application/xhtml+xml' type (given type was '') Multiple occurrences of the 'cover-image' property (number of 'cover-image' items: ).