So, it turns out, it was the cover that they found just 'too' offensive. Not that they would admit it. I posted Zoo under a new name(Night Zero), and with a non risque cover, and, poof, it's up.
Grab it here.
If you already grabbed it from Smashwords, do take a moment to tag the heck out of it with proper tags, and if you're really feeling generous, leave a review on either site. (The Smashwords link is here.)