Try this one:
```
CREATE TRIGGER InsertfehlerPruefung BEFORE INSERT ON Pruefung
BEGIN
SELECT RAISE(ABORT, 'not enough Fahrstundenminuten')
WHERE NEW.theorie == 0
AND (
SELECT SUM(dauer)
FROM fahrstunde
WHERE fahrstunde.schueleremail == NEW.email
) < 180;
SELECT RAISE(ABORT, 'theorie is not 0')
WHERE NEW.theorie IS NOT 0;
END;
```
and see what happens.