Sidebar displayed below comments, not on the side

I need assistance troubleshooting a display problem I am having in Internet Explorer 7.0 which works perfectly in Firefox.

Website address: https://prairietimes.net/

The problem is occurring once you click on the actual entry. The sidebar is no longer displayed on the side, instead it is listed below the comments. I tried decreasing the width of the sidebar by 100px to see if it was a size issue that forced it to display on the next available line but I received the same results.

Any tips would be greatly appreciated.