png background images & the IE problem

[Cowboy Killer]

I have used a png image with a transparency as the background image for a div. Looks great in everything but IE for mac & pc.
See what I mean at www.bangonit.com.au/cj/
Here's how ive declared it:
background: transparent url(../images/site/opac_bg.png) top left repeat;

Any ideas on why this is happening?

[drhowarddrfine]

IE does not handle opacity with png images correctly. Most other browsers do.
IEBlog of that developer (http://blogs.msdn.com/ie/archive/2005/04/26/412263.aspx)
Google for answers but maybe this (http://www.alistapart.com/articles/pngopacity/) helps.