Handling of mobs not in buildings.

src/engine/objects/Mob.java

@@ -418,7 +418,11 @@ public class Mob extends AbstractIntelligenceAgent implements Delayed {
             mobile.guildUUID = guild.getObjectUUID();
 
         mobile.parentZoneUUID = parent.getObjectUUID();
-        mobile.buildingUUID = building.getObjectUUID();
+
+        if (building == null)
+            mobile.buildingUUID = 0;
+        else
+            mobile.buildingUUID = building.getObjectUUID();
 
         if (mobile.buildingUUID != 0)
             mobile.bindLoc = Vector3fImmutable.ZERO;