diff --git a/src/main/java/net/minecraft/server/management/ServerConfigurationManager.java b/src/main/java/net/minecraft/server/management/ServerConfigurationManager.java
index 6f1f505..b4ca8d1 100644
--- a/src/main/java/net/minecraft/server/management/ServerConfigurationManager.java
+++ b/src/main/java/net/minecraft/server/management/ServerConfigurationManager.java
@@ -567,8 +567,10 @@
 
 		int j = p_72356_1_.dimension;
 		WorldServer worldserver = this.mcServer.worldServerForDimension(p_72356_1_.dimension);
+		WorldServer worldserver1 = this.mcServer.worldServerForDimension(p_72356_2_);
+		if(worldserver1 == null)
+			throw new IllegalArgumentException("World not found for dimension " + p_72356_2_);
 		p_72356_1_.dimension = p_72356_2_;
-		WorldServer worldserver1 = this.mcServer.worldServerForDimension(p_72356_1_.dimension);
 		p_72356_1_.getChunkMgr().stopSending(); //before sending S07PacketRespawn
 		p_72356_1_.playerNetServerHandler.sendPacket(new S07PacketRespawn(p_72356_1_.dimension, p_72356_1_.worldObj.difficultySetting, p_72356_1_.worldObj.getWorldInfo().getTerrainType(), p_72356_1_.theItemInWorldManager.getGameType()));
 		worldserver.removePlayerEntityDangerously(p_72356_1_);