PROBLEMS REMOVING RING GEAR AND CARRIER

Your picture isn't the clearest thing in the world. But it looks like you are talking about the cross shaft pin that aids in the c-clip retention.....? You just have to be extremely careful for someone else's stupidity. I am assuming the carrier is still in the pumpkin. About the only thing you can do is improvise. I don;t know how you are going to do it but about your only chance would be to drill the thing out (you may also have to have a tap and die set nearby). Not much else you can do when a screw/bolt is down to the nub.

You other option which may be easier in terms of access. Drilling the cross shaft pin out by going from the top to get to the screw. This may be a little safer due to the fact that you don't have to mess with the carrier. I don't know what much else to tell you.......good luck.