Erwin,
After taking the box apart and reassembling it, I finally got it worked out. I just followed Firefly's Quick Reply Box hack and the box looks like it should now. Thanks for all of the help. If you want my code for the box, let me know. I added a few things to it that make it much easier to use, like the Verify User accepts PMs hack and the Find User Name feature along with a drop down box for the message icons.
By the way, how did you get the Automatic smilies and Fonts in the left side of your box? Can you post the code for that here?