Well Langastino,
I would say a guy with average range wouldn't of been on the ground in the first place so it should of been an error. Secondly, it wouldn't even be on the fielding of the ball, but rather on the errant throw. He never should of thrown the ball and since he did, he pulled the fielder off the bag and allowed a second run to score. The second run should be accounted for by an error even if the first is not.
So ramble on that for a while.