Stuck on top of Hunger Games Sign

I jumped on a pressure plate and I got onto the Hunger Games sign on the ledge and I'm jumping up and down and I'm glitching. On the message it says I can't be in this area. I'm stuck and get get off the ledge of the sign. I have tried to repair the software and I have even uninstalled and reinstalled it back and its still there. (Ali acraft) Help!