Firefox vs IE problem

[exoticsrally]

My forum looks different on Firefox and Internet Explorer. There's an empty space on the right in IE, but works fine in Firefox.

I don't even know where to look for a solution, any ideas?

Here's a screenshot:

[Bawtneez]

IE just plain fails at being an internet browser. End of story. I have had issues with my forum on IE too.

[Dismounted]

Please post a link to your forum. Most likely, you have some sort of side bar that is empty.

[exoticsrally]

<a href="http://www.exoticsrally.com/forum/" target="_blank">http://www.exoticsrally.com/forum/</a>

Thanks for taking a look.