Oops!

After doing a little rooting around with Google, I've managed to figure it out. It turns out that Maya needs to be told to load the IGS importer plugin from within its preferences. < Insert blush emoticon>

I can now load Moi nurbs AND your "test plane".

Thanks for your help, Michael!. I would've given up if you hadn't have made the "test plane". When that never worked I just knew it had to be something else.