Hi Steve, MoI exports to an AI version 8 file, and I think that Inkscape only supports reading in version 9 or higher files. I think that's because they use a PDF library for handling the import, and it's only in AI version 9 and higher that the AI format was changed to be the same as PDF.

See here for some tips on other programs (Mayura draw or creature house expression) you can use to read the AI v8 file out from MoI and save out a PDF file that Inkscape can then read:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4908.4

At some point in the future I do expect that MoI will write PDF files directly as well but I'm not sure exactly when.

- Michael