Thanks for the support.
I don't have any clue what it could be. Maybe the system?
I go over "save as", so I don't have to make a selection. (Export with selection doesn't work neither)
No problem to write an .obj file but iges, sat and step just nothing happens. Seems to be jinxed.
It works with a simple new surface. But if I Paste this "bottle" into the file it doesn't work anymore.
Could you send to me the .step file which you has got of your export?