We played a campaign where one hero stood on top of another hero and revived so that he could move to a free square that was closer to my monsters.

I made the argument that you have to be *adjacent* to a hero and adjacent is not on top of. Am I right in this ruling? With search tokens it specifically says the space you occupy, so I'm assuming that you can't revive in the space you occupy.

You are correct. You have to adjacent another hero to revive them.

I had received conformation from FFG that you do indeed have to be adjacent.