Firefox renders it correctly but IE doesn't. It would appear that IE is not handling th "<br class="clearBoth" />" correctly. Quick Google seems to suggest that this is a common bug with IE. What you need to do is edit your Stylesheet (should be \includes\templates\YOUR CUSTOM FOLDER\css\stylesheet.css) and find the following code:

Code:
.clearBoth {

	clear: both;

	}
change this to read.

Code:
.clearBoth {

	clear: all;

	}