I don't use IE and can't check, but in opera and internet explorer it is black text. However, there is a white check box with a white tick which gets on my nerve but this came with the theme. However, Opera and mozilla show black text in white boxes.
I use cookies anyways, so I only see it occasionally
There's another theme installed too which you can switch to in your profile until I figure out if i can change that flaw in this theme