Lucky: Gotcha - that did the trick
If I could offer up a suggestion as for usability, I think it'd be more intuitive to have the sort order button also displayed on the page where you are actually doing the draging & droping of images (for dotes like me haha)

Once you're already on that page, you can't really tell how things are being sorted.
Regardless, thanks to EVERYONE involved w/zenphoto. Good stuff!