UBB.threads PHP Forum Software Community Forums Resources and Customizing How Do I? Style differences: IE and Firefox

Below is a picture of my Threads board, first in Firefox, then in IE. (Click on the picture to see the original size.)

I spent a lot of time changing the style to look similar to the old Classic board, and I was using Firefox to monitor my progress. When I thought I was done, I checked it in IE, and see that there is lots of blank space between all the boxes.

Anyone had similar experiences? How can I make it look similar in both browsers?

Thanks.