Weird, is it floating in space or is it sitting on something? You will know if it's floating because you cant move anywhere. You have made aiw so I presume it has worked before? Or did you borrow an aiw from another track? You don't need an aiw file if you start it with the isi aiw editor.
Here is what I would check for,
Make sure the start line on the model is at 0.0, 0.0, 0.0.
You haven't missed a bracket in the scn file?
What happens when you open the scn in simed or the scene viewer?
Strip it back to bare minimum, load one gmt at a time (start with the track) and use the scene viewer. Or, if you can remember what you have added and in what order, take the last piece out and work backwards.
Make sure you have all the correct lighting and stuff in the start of the scn file, copy it from another existing scn just to make sure it works.
