Hi Heiner, I've attached a version here which gives no gap - I edited the curves by joining them together, doing a rebuild on it with # of points mode, "Keep corners" turned off, and using 200 points, and then split it into 2 pieces again at the previous end point and then using only one profile for doing the sweep.

You usually don't need to put in so many different profiles when doing sweep, sweep basically automatically puts in a whole bunch of profiles by sliding even just one along the rail or rails - when you are doing Loft on the other hand only the profiles that you specifically put in are used, that's when you would put in more of then to control the shape.

Basically one profile and a rail or 2 rails automatically generates a whole bunch of profiles for you by moving things along the rail.

- Michael