title_body: Help creating a toc.ncx file for compatibility with epub 2
upvoted_answer: Instead of using Adobe DE (which isn't always reliable), you should use the epubcheck validator online on your epub file. http://validator.idpf.org/
  
  You can download a copy of the validator tool on your own machine if you wish. 
  
  That will give you more verbose and  actionable error messages. 
  
  Here are some examples of error messages: https://github.com/IDPF/epubcheck/wiki/Errors (unfortunately this list doesn't seem to be complete or up to date). 
  
  My guess based on a cursory reading of your file is that there are no file references here. Here's an example from one of my own files: 
  
     &lt;navPoint id="d0e1652" playOrder="7"&gt;
              &lt;navLabel&gt;
                  &lt;text&gt;The Silver Link&lt;/text&gt;
              &lt;/navLabel&gt;
              &lt;content src="silver-link.xhtml"/&gt;
          &lt;/navPoint&gt;
          &lt;navPoint id="d0e2128" playOrder="8"&gt;
              &lt;navLabel&gt;
                  &lt;text&gt;Johnny Kinkaid&lt;/text&gt;
              &lt;/navLabel&gt;
              &lt;content src="johnny-kinkaid.xhtml"/&gt;
  
  
  But your .ncx file has an empty reference;
  
        &lt;content src="" /&gt; 
  
  
  As for your other questions, let me say that I have never had to worry about toc.ncx file problems before ... mainly because I auto-generate the file from Docbook. 
  
  The meta stuff you have is exactly what I have; IIRC, it had to do with accessibility and spoken books. 
  
  In my experience, kindlegen almost always produces a working file for kindle if you have given it a valid .epub file.