Well, I produced a midi sample, but it shows me, that "The Extension mid is not allowed" when trying to upload

Try renaming to .midi or .txt

Ok, so here's sample. I had to make an mp3 instead of midi. It takes more place, but is allowed ;P Enjoy!
[III. Toccata: Allegro vivace]

Nice with the car and steamboat horns The stereo effects are a bit weird, as if being in a video game.

It is very short for a concerto movement, is this the entire thing ? Good ideas, and attractive music, but somehow a Toccata which twice collapses into (what seems like) an Adagio does not sound very convincing to me. The brief recapitulation at the end does not save it, it's like you though 'Ah yes, this was a toccata wasn't it, have to tack on a proper ending'. I am not qualified to advise on composing issues, but it seems to me like you could do more with your ideas than just glue them together like this. They are worth it !

Well, actually I'm working on the second version of this movement. I think I should extend it a bit... And I think I shouldn't cut out Adagio. In few toccatas there are similar cases...

Definitely, do not cut it out, as it has great promise. But don't let the toccata give way after just a couple of phrases. Let it run amok for awhile, that's what toccatas do. By then, the adagio will be welcome, and then you could have the toccata come back with a vengeance and work up to a great finish. Such an ABA design is a bit simplistic and traditional, perhaps you wanted something different, but it usually works best.

I agree with techneut, it seems a bit short. You have very interesting musical ideas though. If you could develop them further before the recap it would be even better!