Problem with Q&a plugin.

Hello I've installed the Q&A plugin,
I have trouble with the integration of this puglin to my design:
I wish I could modify it, it probably comes from a <div> missing or somethng, I would need your help to find where it goes wrong, and where to modify the plugin so i don't mess every thing up.

Here is the website:
http://www.provoletroulant.fr/questions/
You will see yourself what it gives.

Thank you very much for your help.