Thanks jcl, but the errors I have mentioned are not in my level but in the Techdemo.
But I will design a new level under A7, maybe something goes wrong when you copy an A6 level.

EDIT
I have made a brand new level in A7 and add some C-Script for the screen and a player.
Even now the screen keeps its default values and will not change to my desired screen resolution and to full screen.
I have no clue at all why this is not working in A7, I have no problem with this in A6.