"Create Account" form appearing on every page

Hi there,

I just updated MarketPress on a site that's been running it without issue for months, and all of a sudden on every page EXCEPT our "Shop" page, an ugly, unstyled form is being injected below our footer that says "Create Account." Inspecting the elements, it looks like there are lightbox classes present (even though I disabled the Lightbox checkbox in the Presentation settings pane).

This is critical—it's adding the form to every page, including our home page, and it's a ridiculous eyesore. I can't figure out where it's coming from or how to disable it.

Please assist ASAP.