for some reason, your theme (?) seems to be using a script to insert the CSS class .threecol
into the containers of the posts in the category page, to format the main posts into three columns, but unfortunately does that also for the posts in the footer list.
maybe also ask in http://wordpress.org/support/plugin/flexible-posts-widget
I am sorry, the problem is not resolved. flexible-post-widget does not affect layout.
A second problem was detected: The category pages show a different layout between languages. The emglish layout shows 2 column layout. A 4 column layout is wanted as shown on german pages.
I assume that both problems might have same cause.
Please help!!