I am having a very similar issue in FCP7 right now. I have a .png created in Photoshop (which I do ALL the time) and, no matter what I do, FCP brings this file in with the transparent portion filled in with white.
I have been doing this for months and none of my settings have changed, but for some reason this one file just won’t work.
I have tried it on two different machines with no luck – the same problem on both. To make matters even stranger, when this file is reopened in CS4 Photoshop, it appears as it should.
What causes a transparent area in a .png to not be transparent in FCP7?