It could be that the protection stone wont allow you because its overlapping another. I don't really know :3
Yes, Artemis is right, there may be one under you, far far away, they can be 59 blocks away and it will be overlapping.
I was right for something once :O Its a miracle I've done it! I've did it mom! I'd like to thank the academy, that hobo across the street and my dead goldfish for never stop believing in me.