Hmm, I did check it in IE before posting and it worked on my computer and I just checked your journal on Firefox and it looks fine.

Do you happen to have an older version of IE? I think older IE versions don't display .png transparency properly so instead of the shadow part of the header going transparent, it may just be making the shadow on a white background. If that's the case, you may just have to upgrade to whatever the newest version is. Hope that helps!