I created an epub version of The Kewpie Killer using Sigil. Sigil verified the epub format and I used the final file to upload to Amazon KDP. Then, I uploaded the same file to Smashwords only to have the autovetter balk that the copyright page was not up to their standard.
I modified the copyright page to match Smashwords requirements and once again the autovetter made the same complaint. Of course I fiddled with the file and resubmitted it 4 or 5 times before I gave up.
Since the emails I received from Smashwords after each attempt reported that "We have run EPUBcheck on your file, and it has passed!" I wrote to customer service.
Their reply was "It looks like a glitch. The vetters can override the error."
Now, I'm waiting for the "vetters".