Error codes

[shaneco1010]

Hello, I am getting the following error codes when trying to upload my epub to Ingram. Does anyone know what any of them mean?

[ERROR]content.opf: 2,133: URL expected instead of calibre:

[ERROR]content.opf: 22,64: Undecleared prefix: calibre

[ERROR]content.opf: 23,54: Undefined property: belongs-to-collection

[ERROR]content.opf: 24,54: Undefined property: collection-type

[ERROR]content.opf: 29,121: Undecleared prefix: calibre

[ERROR]titlepage.xhtml: 10,73: value of attribute "http-equiv" is invalid; must be a string matching the regular expression "([Dd][Ee][Ff][Aa][Uu][Ll][Tt]\-[Ss][Tt][Yy][Ll][Ee])|([Rr][Ee][Ff][Rr][Ee][Ss][Hh])"

[ERROR]titlepage.xhtml: This file should not declare in the OPF the properties: svg calibre:title-page

[ERROR]index.html: 2,106: value of attribute "lang" is invalid; must be an RFC 3066 language identifier

[ERROR]index.html: 2,106: value of attribute "xml:lang" is invalid; must be an RFC 3066 language identifier

[ERROR]index.html: 12,73: value of attribute "http-equiv" is invalid; must be a string matching the regular expression "([Dd][Ee][Ff][Aa][Uu][Ll][Tt]\-[Ss][Tt][Yy][Ll][Ee])|([Rr][Ee][Ff][Rr][Ee][Ss][Hh])"

[ERROR]nav.xhtml: 5,73: value of attribute "http-equiv" is invalid; must be a string matching the regular expression "([Dd][Ee][Ff][Aa][Uu][Ll][Tt]\-[Ss][Tt][Yy][Ll][Ee])|([Rr][Ee][Ff][Rr][Ee][Ss][Hh])"

[Evil Overlord]

In brief, Ingram's EPUB verifier does not permit the "belongs to collection" property. I've been discussing this with them for well over a year. They say that they are working on resolving it. (Of course, they said that a year ago, but I hold out hope.) For the moment, I make a special Ingram version of each EPUB for submission to them - exactly the same, except for deleting this property.

I use Sigil for book prep, and it's quite easy to delete the property from its metadata manager.