Question about toc

I'm trying to make a toc based on the Moby Dick example, and KindleGen is
having troubles finding an intact toc.

I have made just one toc.xhtml, without a short toc.xhtml; please tell me
if this is asking for trouble. I've attached a configuration of the
toc.xhtml, plus package.opc if that helps which I've revised to better
follow the footsteps of Moby Dick example.

KindleGen is giving me:
kindlegen A\ Few\ Hand-Picked\ Titles.epub -o A\ Few\ Hand-Picked\
Titles.mobi

*************************************************************
 Amazon kindlegen(Linux) V2.9 build 1028-0897292
 A command line e-book compiler
 Copyright Amazon.com and its Affiliates 2014
*************************************************************

Info(prcgen):I1047: Added metadata dc:Title        "Unvera Announces New
Kool-Aid Line"
Info(prcgen):I1047: Added metadata dc:Creator      "C.J.S. Hayward"
Info(prcgen):I1047: Added metadata dc:Publisher    "C.J.S. Hayward
Publications"
Info(prcgen):I1047: Added metadata dc:Rights       "This work is shared
with the public using the CC0 license."
Error(core):E1005: Could not access file.
      in file: /tmp/mobi-ssdf2i/OPS/toc.xhtml
Warning(prcgen):W30006: Reading the Epub navigation file failed
/tmp/mobi-ssdf2i/OPS/toc.xhtml
Error(prcgen):E24012: Epub Navigation file could not be built.
​
​Thanks for any help sorting this out,​

-- 
Christos Jonathan Seth Hayward,
An Orthodox Christian author.
Amazon <http://amazon.com/author/cjshayward> - email
<christos.jonathan.hayward@gmail.com> - made-to-order ebooks
<https://ebook-builder.gifts> - website <https://cjshayward.com>.
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<https://gofundme.com/the-holy-mountain>