This is in reference to the "unsubscribe" button which appears for any forum which you are currently subscribed to. It appears the image for this element is missing, causing the button to be invisible. This is an issue across all of the themes available.
The broken image path -> http://www.clanaod.net/forums/images...cribed_40b.png
What it should be -> http://www.rockkrawler.org/images/mi...cribed_40b.png