(this happened a day ago I don't remember exactly)
I started hosting a small server for me and my friends to play, it had 1gb of ram, when ever some one attempted to ride a horse the player that attemted to ride it would be disconnected and not able to reconnect due to an "end of stream" error, how ever when trying to reconnect it would say (on the players screen) something like "error at mounting point" so far the only way im able to fix this is by deleting the players .dat file thats in the world/players folder. I can supply more information if needed