Huge space showing in first category row...can't find it!

[mishi]

I have a huge space after the first category row or product row on all of my pages. I know it must be something in one of the divs but I have used Firebug and searched through the scripts and css and can not find it. I have been working on this for weeks! Any help would be appreciated

Here is the link:
http://rsa-inc.com/parts

Thanks in advance for any help you can give!
Mishi