Fixes boy0001/FastAsyncWorldedit#1116

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/v0/BukkitChunk_All.java

@@ -178,12 +178,14 @@ public class BukkitChunk_All extends IntFaweChunk<Chunk, BukkitQueue_All> {
                         int xx = bx + x;
                         int biome = biomes[index] & 0xFF;
                         if (biome == 0) continue;
-                        if (biome == -1) biome = 0;
+                        if (biome == 255) biome = 0;
                         Biome bukkitBiome = adapter.getBiome(biome);
+                        if (bukkitBiome != null) {
                             world.setBiome(xx, zz, bukkitBiome);
                         }
                     }
                 }
+            }
         } else if (index != 0) {
             if (place) {
                 layer--;