Yeah it seems odd. I would close C out and save the render again. I didn't try another program, but gimp loaded it with a couple of minor errors about sorted tags (I get that from other tifs tho) The other message was odd. Bad value 1 for extra samples. However, it loaded fine with both alpha maps/premultiplied.

The printing function in carrara won't work for me. It spits out a page w/ a title on it. Never have got that to work. Can you print out of carrara?

No need to think outside the box....
    Just make it invisible.