Thanks.. told my client to send me step instead of Rhino 6.0 files.. however it didn't went well and I had to upgrade Rhino.
I fully understand, I really hate the Rhino format sometimes, or what Rhino does there. If only they switch to step file format only :-)

I'll put in a warning message if you try to open a Rhino v6 file, that way it won't be as mysterious.

- Michael