Ok dude
and thanks for your help!!!
edit
so i did an experience
I use to work with a lot of programms opened and such
so i closed a lot , as much i can and it seems it helps the stencyl to do export properly.
I export twice and i didnt got the error "can"t write""
so it seems maybe it's my computer wich use too much programm at the same time , so the stencyl have problems to export properly , why? because the game is huge , so he needs more memory ressources than usual.
I think it could be the key , not sure but it makes sense.
Also when balloons failed , it was maybe an error with the downloads and such