Transparent PNGs on top of a bg

i read this article and wanted to use it on a site im doing:

http://www.alistapart.com/articles/pngopacity/

now, in firefox all is well, and it works great. when i test this in IE, it stretches the menu images and doesnt look like it should. If anyone can shed some light on this, that would be tremendous as i’ve gotta get this thing working so that i can rotate out the backgrounds whenever i want.

you can grab the working files here:

http://www.reintroducing.com/apnw/deploy.zip