Can you share the AI file with us?
So I did a little testing and the problem was that the Illustrator file contained a placed Photoshop file.
Looks like the conversion cant happen if there is bitmap info in the Illustrator file.
Is that correct?
(kind of like how you cant make Illustrator layouts that include photos into a symbol within Illustrator.)
It's the placed file that causes the issue, but if you rasterize the placed file in AI, FW will open the file.
Just like with the making of a symbol.
Needs to be rasterized first.
(loving your tuts on Adobe TV, btw...)
Thanks very much, Thomas!