There is no problem with the Church officially defining a doctrine which is not explicitly in Scripture, so long as it is not in contradiction to Scripture.
The Catholic Church was commissioned by Christ to teach all nations and to teach them infalliblyguided, as he promised, by the Holy Spirit until the end of the world (John 14:26, 16:13). The mere fact that the Church teaches that something is definitely true is a guarantee that it is true (cf. Matt. 28:18-20, Luke 10:16, 1 Tim. 3:15).
Unless, of course, it's not true, then, by definition, the Church never taught it, even if it did teach it.
I think I understand now!
Can we come up with a list for this one?
1) The earth is flat. Galileo got in big trouble for doubting this "Church teaching."
2) Heretics should be burned at the stake. This Church teaching was true at one point...must still be true. Ouch! Quit, you're hurting me! Hey, that's hot!!! Stop that!!
More???