Breaking layout

I am building a child theme from Thematic. I have two post published and everything looks fine, but when I add another post it breaks the layout in the footer area (sort of). The 3 footer columns remain intact, but the background color acts as if it is breaking (it sort splits in 2 and moves to the bottom. I know that is hard to visualize, but I am developing locally, so can’t give a link, sorry.