Stylevar edits (and reverts) causes problems

[The Vegan Forum]

I've just discovered that on our vB4 test site, a 3.*skin we are using (which someone ported over to vb4 for us) has serious problems. The header is what have been modified by our hired helper, and that' where the problems occur as well.

Header related stylevars (header_background, header_color) controls other areas than they are supposed to, and reverting the parameters don't help.

Here's an example: after having reverted header_background, we get this result (see image):
Two dark, vertical lines appear on each side of the forum, but the header background isn't changed.

Dos anyone know how we can fix this?