Well the logo (page_header_bblogo.png) appears a bit darker then the background color of the header. You clearly see a grey square now. When overwriting the blue logo with the original green one, the same problem appears (thought perhaps the background color was made too dark).
Swithcing the theme back to the normal kakumei, the logo displays correct. Overwriting this with the blue logo gives no problems either.
So there is a bug in the blue kakumei theme, plz fix :)