I have created a new splash page for my clients, everything works great, but in IE i have that png problem... I fixed it, and it works perfect, but only when the picture has fade in completely. The time that the image fades in and out, the png has a black background.
That is one of the many IE bugs that made IE the most hated browser.
PNG transparency and opacity just don't work together.
There is nothing you can do about it.
I always replace the transparent 32-bit-png with a jpg (or a 8-bit-png) via a browser specific css-file for IE. (conditional comments or gantry browser detection)