NEED HELP!

I have this layout: http://www.languageisavirus.com/mydesign/index.html and I want to make the right colum 340px width.

I have tried making the other divs larger and the subcolumn wider and even making the background graphics in the subcolumn wider but the whole thing just FREAKS OUT and doesn't work..

it looks easy as pie! why won't it work??

Main Page: http://www.languageisavirus.com/mydesign/index.html
CSS: http://www.languageisavirus.com/mydesign/style.css