[SOLVED] Problem with header on single posts

Wasn't sure where to post this.

I installed a plugin for related posts and I am seeing some wacky things.

On the post "page" it works fine. It shows up under the individual post as expected. But on single post pages the plugin is appearing at the bottom of the post as expected AND what looks like above the header; pushing the header info (logo, search, etc.) down.

At first I thought that this was an issue with the plugin, but I think it has somethign to do with the theme as it happens on all similar working plugins.

Is there a setting that controls this?

Here is the site: http://www.vectorcast.com/blog/

Thanks for any help!