extra space help

http://ghostsofwarx.darkbb.com/forum.htm

Now as you can see on the right side beside the chatbox and threads, there is extra grey space.

I don't want to add anything else, but I want to extend the middle part to the right part so that it is not so squished.

Is this possible because if it is, it would be a big help

Admin Panel // General // Configuration // Pages structure // Forum width (number or %) // Set it to something like 80% if it doesn't work set it bigger or lower.

No, it still doesn't work. I've tried every number divisable by 10 up to 100 and nothing changed