Oops! This matters.

src/main/java/net/minecraft/server/World.java

@@ -136,8 +136,6 @@ public class World implements IBlockAccess {
             flag = true;
         }
 
-        // Craftbukkit start
-
         this.q = (WorldProvider) object;
         this.q.a(this);
         this.G = this.a(this.t);

src/main/java/net/minecraft/server/WorldServer.java

@@ -25,8 +25,8 @@ public class WorldServer extends World implements BlockChangeDelegate {
         this.D = minecraftserver;
 
         // CraftBukkit start
-        this.world = new CraftWorld(this);
         this.server = minecraftserver.server;
+        this.world = new CraftWorld(this);
         this.manager = new PlayerManager(minecraftserver, this);
     }