Your maybe making the entities fall too fast. I had a run in with that. Also, if you rotate abjects and collide, it causes problems. And if you move the item to be collided against, this also causes collision probelms.
Make sure as well that your doing the collisions the right way round. The moving entity always has to be the first entity, and the other one, the second (and stationary) one.
Make sure as well that your doing the collisions the right way round. The moving entity always has to be the first entity, and the other one, the second (and stationary) one.
Collisions first_entity,second_entity,2,2