You guys close threads too prematurely!!! I'm having the same problem, and I don't have that plugin installed (share this). The ones I have installed are
.html on pages
Page links to
Tiny Contact Form
Formbuilder (yes I need both forms)
Can't really eliminate any of these because the site's pretty much complete, but it would good to know next time. It's happened on one other site too. This has only happened with the newest version of Atahualpa. I had several of the same plugins on a prior version with no problem.