IDPF, the consortium that promotes the .epub standard, has released a tool named epubcheck.
It is available both via an online web-app here, or as a stand-alone program here.
There is also another tool called FlightCrew, available here; this is also integrated within Sigil, a full fledged epub editor (available here).
All these tools are free and cross-...
That would mean your EPUB does not have a proper ZIP file structure.
You can try listing the content of your file with a normal zip unpacker, or test it with a real epubreader. If those do not complain, it could mean that FlightCrew has a bug.
For CreateSpace you essentially need to provide a PDF and do the layout by combining your output with images in the form of PDF output. To conform to their formats, you would still need a template for the editing software that you use, that generates a PDF that can be merged with such templates (and not come into the margins as they warn you not to).
The first error message is telling you that the file referenced is not declared in the <manifest> section of the content.opf file. The second one is telling you that the file exists in your epub, but is not declared in the <manifest> section of your content.opf file. The important thing to note is that in the error messages you listed, there are ...
Unfortunately, there's a lot more wrong than the errors listed. The first line needs to be (adding the question mark):
<?xml version="1.0" encoding="utf-8" standalone="no"?>
After you correct that and validate that, you will turn up 100s of validation messages -- not only in the opf file but also the xhtml files.
This tells me that your method for ...
This sounds buggy or perhaps you are viewing your directory incorrectly. First, are you using the latest validator? Are you validating the file as an epub2 file instead of an epub3? (You should make the files epub3 even if you are not using epub 3's advanced features). FYI, use of toc.ncx is deprecated starting in epub3. Epub 3 validation shouldn't even ...
I posted an issue at the epubcheck site.
Someone there knew right away what the problem was.
This is acceptable:
<p>Text <span class="red">red</span> regular.</p>
This is acceptable:
<p>Text <span style="color:red">red</span> regular.</p>
This is not acceptable, and is what I had:
<p>Text <span ...
There doesn't appear to be an issue with the code after I tested it in a dummy ePub with ePubcheck 3.0. Since you haven't mentioned how the ePub was created I would trouble shoot by:
Creating a new XHTML file and re-doing the contents of the old XHTML file in it to make sure there isn't any issues with the file or if the file is corrupted.
Check to make ...
Your eBook has been rejected for improper capitalization. The first
letter of all words in the title, subtitle and author name should be
capitalized, except for the following words: a, an, and, for, from,
of, or, the, to. The first and last word of the title and subtitle
should always be capitalized.
This error is because you have a title or author ...