Program: 1839
Project: 1839
Buggy source:
/** 
 * Purchase a teleport
 * @param player
 * @param wizard
 * @param op
 */
public static void buy(Player player,HumanNPC npc,String op){
  if (EconomyManager.hasEnough(player,UtilityProperties.getPrice(op)) || !EconomyManager.useEconPlugin()) {
    boolean canSend=false;
    Wizard wizard=npc.getType("String_Node_Str");
    String msg=ChatColor.GREEN + "String_Node_Str" + StringUtils.wrap(EconomyManager.format(EconomyManager.pay(player,UtilityProperties.getPrice(op))));
    if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(wizard.getCurrentLocationName()) + "String_Node_Str";
      if (teleportPlayer(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(wizard.getMob().name().toLowerCase().replace("String_Node_Str","String_Node_Str")) + "String_Node_Str";
      if (spawnMob(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(wizard.getTime()) + "String_Node_Str";
      if (changeTime(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(player.getWorld().getName()) + "String_Node_Str";
      if (toggleStorm(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(wizard.getCommand()) + "String_Node_Str";
      if (executeCommand(player,npc)) {
        canSend=true;
      }
    }
 else {
      msg=ChatColor.RED + "String_Node_Str";
      canSend=true;
    }
    if (canSend) {
      player.sendMessage(msg);
    }
  }
 else {
    player.sendMessage(MessageUtils.getNoMoneyMessage(player,op));
  }
}

Fixed version (ground truth):
/** 
 * Purchase a teleport
 * @param player
 * @param wizard
 * @param op
 */
public static void buy(Player player,HumanNPC npc,String op){
  if (EconomyManager.hasEnough(player,UtilityProperties.getPrice(op)) || !EconomyManager.useEconPlugin()) {
    boolean canSend=false;
    Wizard wizard=npc.getType("String_Node_Str");
    String msg=ChatColor.GREEN + "String_Node_Str" + StringUtils.wrap(EconomyManager.format(EconomyManager.pay(player,UtilityProperties.getPrice(op))));
    if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(wizard.getCurrentLocationName()) + "String_Node_Str";
      if (teleportPlayer(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(wizard.getMob().name().toLowerCase().replace("String_Node_Str","String_Node_Str")) + "String_Node_Str";
      if (spawnMob(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(wizard.getTime()) + "String_Node_Str";
      if (changeTime(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap(player.getWorld().getName()) + "String_Node_Str";
      if (toggleStorm(player,npc)) {
        canSend=true;
      }
    }
 else     if (op.equals("String_Node_Str")) {
      msg+="String_Node_Str" + StringUtils.wrap("String_Node_Str" + wizard.getCommand()) + "String_Node_Str";
      if (executeCommand(player,npc)) {
        canSend=true;
      }
    }
 else {
      msg=ChatColor.RED + "String_Node_Str";
      canSend=true;
    }
    if (canSend) {
      player.sendMessage(msg);
    }
  }
 else {
    player.sendMessage(MessageUtils.getNoMoneyMessage(player,op));
  }
}