Related Posts Plugin makes right column fall under content

I have a 2 page cutline theme here(i deleted the left column) and for some reason when I install this Related Posts Plugin,

http://wordpress.org/extend/plugins/wordpress-23-related-posts-plugin/

The right column falls to the bottom of the page, as if the main content column is now too wide. I looked in the code to see if there was any width noted but there wasn’t. Anyone know how I can prevent this from happening?