Actually, I beleive that place is controlled by 'cleartable' class in your stylesheet. You might want to set that color to white.
The text in the last post column, I think that's controlled by the 'posttime' class.
This will help you a bit:
http://www.infopop.com/support/ubbthreads/css_screens.htmlAlthough there are a few things incorrect with it. It says cleartable is only used in the admin interface. But cleartable is really that clear box (which is blue on your forum).
I think all your issues are CSS related.