Add border: 1px solid #000000; in the style area on the right side of the border category. Then leave the border background at #ffffff/#FFFFFF/white/#FFF/#fff.

Thanks for the help. I tried this and it adds a darker border around the white outside border. It doesn't eliminate the white border. Is there a way for the darker border to replace the white border?

For the background of the border, put #000000.

Wouldn't this then remove the white lines between the threads?

Nope. Backgrounds and borders are completely different parts. So your .tborder/Table Border CSS block should look like this: (of course, keep the font color to what you already have)
Attachment 45264

I have done exactly this and what I am saying is, the outside border stays white. Adding #000000 to the border only adds a black line outside of the white border. The white border doesn't disappear. What I am trying for is to have the lines white and the outside border dark with no white border within it.

I have seen it done. I think we are missing a code here.

Here is a site where it works:
http://www.ulctribal.com/forum/

Here is what my site looks like when I add the black border.

http://www.interfaithforums.com/forum.php