Re: IE 6 breaking tables.
I am the developer of this theme, and I also saw your post in my forums (will answer shortly.)
First: This was my first theme and an old one, it needs to be updated. Which is probably why you are having issues. I plan to update all of my bbPress themes this week.
Second: As a temporary fix, try:
#front-page #discussions {
width: 590px;
overflow: hidden;
float: right;
}
Let me know what happens.