République démocratique allemande
Ernst participated in 1980 UEFA European Under-18 Championship which was held in East Germany as the captain of the East Germany Junior team. 16 May Weissenfels East Germany 0-1 Bulgaria, 18 May Torgau East Germany 2–0 France, 20 May Magdeburg East Germany 0–0 Netherlands, East Germany resulted as the second of the group B, didn't proceed to the semifinals.