"Image Not Found" icon appears with 5.24 - linked to www.hbo.com! Ad banners planned?

[w-sky]

After updating from 5.21 to 5.24, a green "image not found" icon appeared right on the skin that I use (see picture)!

The tool tip text for the icon is "Visit 6 Feet Under Website" and it links to http://www.hbo.com/

That icon is not visible with other skins. This one ("Red Pearl") is quite special because of its shape, and I guess, that for that reason this new (not yet official?) ad icon(?) shows here and not with other skins.
I have been using this particular skin since a long time with Winamp 5, so I am quite sure the icon does not come from the skin.

Let's get rid of it! How can it be disabled?