Should not be putting empty maps into the collection with id 0.

src/engine/InterestManagement/HeightMap.java

@@ -149,8 +149,6 @@ public class HeightMap {
             }
         }
 
-
-        HeightMap.heightmapByLoadNum.put(this.zoneLoadID, this);
     }
 
     public HeightMap(Zone zone) {
@@ -169,7 +167,6 @@ public class HeightMap {
         this.fullExtentsX = halfExtentsX * 2;
         this.fullExtentsY = halfExtentsY * 2;
 
-
         // We needed to flip the image as OpenGL and Shadowbane both use the bottom left corner as origin.
 
         this.heightmapImage = null;
@@ -187,8 +184,6 @@ public class HeightMap {
             }
         }
 
-
-        HeightMap.heightmapByLoadNum.put(this.zoneLoadID, this);
     }
 
     public static void GeneratePlayerCityHeightMap() {