Overlapping PNG's in IE7

[interpolerater]

I've been searching for a solution to this problem on the internet, but I have yet to find one regarding IE 7. My page has two PNG images one on top of the other. Both are partially transparent and both are on top of a JPG image. For some reason, where ever the upper png is overlapping the lower png in transparency, it is instead solid black. It makes for a very very ugly effect and I really want to get rid of it, but I'm not sure how.

Click here to view the page (http://interpolerater.co.cc/)

Thanks!

[KDLA]

You might check the transparency setting type - index or alpha.