Sweet Dreams Are Made Of Teeth has been reviewed - after 12 days - for inclusion in the Premium Catalog. It was sent back to me because of an improperly formatted .ncx file. If you are saying 'Bwa?' right now, congratulations! You appear to be telepathic and are getting signals directly from my brain.
Turns out the .ncx file is made automatically and is not something you build separately, so don't worry about that. What they MEAN is that my Table of Contents was messed up. I'd tested my table of contents when I uploaded it, and it worked. The only oddity was that it showed an extra link to chapter 1, but since I hadn't put any other links in and the ToC worked just fine, I let it go at the time.
It worked out for the best. Because Smashwords really is pretty helpful, they pointed me to the specific part of the Style Guide involved. There were two things that I hadn't done. One, apparently your ToC absolutely must be in 'normal' style, not any other. Fine, I made it 'normal' style instead of 'heading', the other option that's allowable for chapter headings. But I don't think that was the issue.
The issue was Hidden Hyperlinks. You see, Microsoft Word hates you. It is not your friend, it won't call you in the morning, and it's badmouthing you behind your back to your friends. It is inserting 'hidden' hyperlinks the whole time you're working. It doesn't tell you, and it doesn't show them on the page, and they don't do anything useful for you whatsoever. It doesn't even show them on your hyperlinks list. Their ONLY purpose is to totally screw up an .ncx file. Fortunately, when you're adding your own bookmarks there's a button you can press to see them, and then you can erase them. DO THIS LAST. The absolute last thing before you save and quit. Why? Because Microsoft Word hates you so much it will keep adding them, and the only way to be sure they're all erased is to save immediately after they're deleted.
On the plus side, this gave me an excuse to fix a leftover typo someone spotted. I hate those. It's like giving a child legos. You will never, ever find them all. And after I reuploaded I checked the new versions and the ToC looks nice and clean.
I just wish it didn't take 12 days to review!
As a side note, do not ever, ever get so busy proofreading and preparing your work for publishing that you forget to do new writing of your own. You will curl up and die, left to be blown around by life like a dry and withered spider corpse.