Mega Menu is desplaying funny

The menu displays outside of the window frame. See image: http://www.screencast.com/t/HL8gSgtEky

Here is my set up: http://www.screencast.com/t/ba2tgblN

Please can you advice what I need to do to have have the Mega Menu displayed correctly?

Site in question: http://69.195.124.212/~sunnlede/

Cheers!