The black border around the windows shown in your screen shot are not appearing when I installed on my 64bit vista sp2. In fact, the entire theme looks a little different.
I love what i see in the screen shot but because the windows are all white to the edge, it is hard to distinguish where one ends and another starts. This was the only reason i decided to use someone elses theme.
Any ideas on how to fix this problem? Am I doing something wrong? What OS is previewed in the screenshot?