This applies to other themes. My example is for the popular theme Zukitwo http://browse.deviantart.com/?qh=§ion=&global=1&q=zukitwo#/d3df2ot
"GTK2 ENGINES REQUIREMENT
GTK2 engine Murrine 0.98.1.1 or later.
GTK2 pixbuf engine or the gtk(2)-engines package."
I have both of those packages installed but the theme is not rendered properly.
Please see screenshot for reference.