Overlap of quantity discounts and order box

At this URL

http://www.coda.org/estore/index.php?main_page=document_product_info&cPath=1_5&products_id=46

I'm getting an overlap of two boxes.

I'm savvy enough to track down the .php or the .css to adjust this,
but I'd like to avoid that if there's a KISS solution instead.

On the educational side, what kind of things might be making this
happen? What could make it overlap itself?

Thanks,

Dr Doug

Somehow, the mainWrapper width has been set to 750 which is causing the center column to not have enough room to prevent the overwrap. Most sites are 900+ due to today's larger monitors. For flexible width, set a percentage like 80%. Whichever you think looks best to the customer.

You'll need to adjust the mainWrapper width in the stylesheet.css. Of course, that will throw off your header image so be aware of that as you do.