Hm.. I got the background loaded fine, and, like you, left one Black tile for transparancy. But the wrong colour was made transparent, in the Rom- any idea how I can fix it? I haven't closed down NTME yet, so i think i'm still safe.
Edit- Nvm, I think I know what I did- the black wasn't the first colour in the palette, as it probably should have been. I'll fix it now..