I apologize if this is on the wrong section, but I need another set of eyes.

I have the latest version of Zen-Cart
I'm using a modified version of the 'Red Passion' template
I have the '3 Column Mod' Installed

My problem is in Firefox (latest version) oddly enough.

The 3 column layout breaks. I know a fair amount of CSS, but virtually no php. I can't track down what is breaking the layout.

URL: http://www.tomwatersonline.com

Click on the Shirts or Pants section to see what I mean. It doesn't do it everytime, but if it looks ok and I refresh the page, it breaksdown again.

Thanks for any help!