Width of Div altered when height is specified in IE

I’m working on CSS-ifying a table layout, and have come across an odd “bug” in IE.

I’ve attached some sample code and CSS to demonstrate, but the basic issue is this.

I have a three column liquid layout. In the center/main column, I need to have a module with its height specified to be 175px, and its width 100% of its available space.

Simple right… Well for some reason in IE6 on my machine, when I specify the height of the div in the CSS, the div’s width is shortened by 3 pixels on both the left and right sides.

I’ve attached some code. #brandDiv is the div in question. It should be as wide as the blue bar below it, but it isn’t.

Anyone have any suggestions?