edit the style.css file.
go to
#branding {
border-top: 2px solid #bbb;
padding-bottom: 10px;
position: relative;
z-index: 9999;
}
change the value of z-index to 3.
The z-index of the fanctbox div is 1102, so anything under 1102 will make the header appear under it I suppose.
Hope I helped.
