Updated for server v0.2.4. Thanks to ricin for testing an independent fix.

src/MinecraftSetBlockProxy.java

@@ -26,7 +26,7 @@ import com.sk89q.worldedit.blocks.BaseBlock;
  *
  * @author sk89q
  */
-public class MinecraftSetBlockProxy extends el {
+public class MinecraftSetBlockProxy extends em {
     /**
      * Edit session.
      */

src/ServerInterface.java

@@ -202,7 +202,7 @@ public class ServerInterface {
         }
         proxy.setEditSession(editSession);
 
-        bg treeGen = new gy();
+        bi treeGen = new ha();
         return treeGen.a(proxy, random,
                 pt.getBlockX(), pt.getBlockY(), pt.getBlockZ());
     }