I'm having a problem with this site in that the png transparencies aren't working in IE 6 or 7. I added a JavaScript file that I've used before to fix it but it's not working here. I may not be calling it correctly or something. The file is pngfix.js and I'm calling it in the header like this:

<!--[if lt IE 7]>
<script defer type="text/javascript" src="pngfix.js"></script>
Any ideas what I'm doing wrong and how to fix it? One thing that's weird about this to me is that before when I've used png files, they've worked in IE7 and this one doesn't. Also, the way I'm calling the script doesn't make sense if it's not working in IE7, either. Anyway . . . help?