Hi John.
I know I am a couple of years but this might help some other people. Save the CAD file as extension IGES and import it to DesignModeller. When you generate it under '0 Parts, 0 Body' in DesignModeller, you should get a certain # of Parts and Body for each distinct part. If that doesn't work, you can try uninstalling the software and installing it again, and following the same steps above.
Hope this helps.
You are navigating away from the AIS Discovery experience