I'm new to bukkit and I do not know the full API. Unfortunately I have a problem I can not solve. I double checked the code Puu times but have not found the problem. I therefore ask you if you can help. So working adun my fork of the plugin "Survival Games by Double0Negative"Unfortunately, among the problems reported to the original author there is also what I found and I would like to fix that. So the code "incriminated" can be found here and are interested in the event is in the class DeathEvent this class call the method killPlayer on the class Game. The error originates when a player is killed by a potion or an arrow (bow) (I have not verified if also with the killing of a mob); the line that triggers the error is: Code:java p.teleport(SettingsManager.getInstance().getLobbySpawn()); The function can find the line 562 of Game.java (link above) Furthermore, the function killPlayer() calls (if there are no more player) function playerWin() which in turn has a teleport. If I comment out the code of the teleport I have no error. If, however, teleport players who were killed in the way I explained before the teleport function returns an error. The stack trace can be found here . When the player dies from falling damage or killed by a player with such a sword the same teleport function does not generate errors. Thanks again for everything and sorry if the post is so long but I really need your help.