Program: 1965
Project: 1965
Buggy source:
/** 
 * Buy an armor repair
 * @param player
 * @param npc
 * @param armor
 * @param armorName
 * @param plural
 */
private void buyArmorRepair(Player player,HumanNPC npc,ItemStack armor,String armorName,boolean plural){
  String msg="String_Node_Str";
  if (!EconomyHandler.useEconomy() || EconomyHandler.canBuy(Operation.BLACKSMITH_ARMOR_REPAIR,player)) {
    if (EconomyHandler.useEconomy()) {
      if (npc.getBlacksmith().validateArmor(armor)) {
        if (armor.getDurability() > 0) {
          double paid=EconomyHandler.pay(Operation.BLACKSMITH_ARMOR_REPAIR,player);
          if (paid > 0) {
            armor.setDurability((short)0);
            msg=ChatColor.GREEN + ("String_Node_Str") + StringUtils.wrap(armorName);
            if (plural) {
              msg+="String_Node_Str";
            }
 else {
              msg+="String_Node_Str";
            }
            msg+=StringUtils.wrap(npc.getStrippedName()) + "String_Node_Str" + StringUtils.wrap(EconomyHandler.getPaymentType(Operation.BLACKSMITH_ARMOR_REPAIR,"String_Node_Str" + paid,ChatColor.YELLOW))+ "String_Node_Str";
            player.sendMessage(msg);
          }
        }
 else {
          player.sendMessage(ChatColor.RED + "String_Node_Str");
        }
      }
 else {
        player.sendMessage(ChatColor.RED + "String_Node_Str");
      }
    }
 else {
      player.sendMessage(ChatColor.GRAY + "String_Node_Str");
    }
  }
 else   if (EconomyHandler.useEconomy()) {
    player.sendMessage(MessageUtils.getNoMoneyMessage(Operation.BLACKSMITH_ARMOR_REPAIR,player));
    return;
  }
}

Fixed version (ground truth):
/** 
 * Buy an armor repair
 * @param player
 * @param npc
 * @param armor
 * @param armorName
 * @param plural
 */
private void buyArmorRepair(Player player,HumanNPC npc,ItemStack armor,String armorName,boolean plural){
  String msg="String_Node_Str";
  if (!EconomyHandler.useEconomy() || EconomyHandler.canBuy(Operation.BLACKSMITH_ARMORREPAIR,player)) {
    if (EconomyHandler.useEconomy()) {
      if (npc.getBlacksmith().validateArmor(armor)) {
        if (armor.getDurability() > 0) {
          double paid=EconomyHandler.pay(Operation.BLACKSMITH_ARMORREPAIR,player);
          if (paid > 0) {
            armor.setDurability((short)0);
            msg=ChatColor.GREEN + ("String_Node_Str") + StringUtils.wrap(armorName);
            if (plural) {
              msg+="String_Node_Str";
            }
 else {
              msg+="String_Node_Str";
            }
            msg+=StringUtils.wrap(npc.getStrippedName()) + "String_Node_Str" + StringUtils.wrap(EconomyHandler.getPaymentType(Operation.BLACKSMITH_ARMORREPAIR,"String_Node_Str" + paid,ChatColor.YELLOW))+ "String_Node_Str";
            player.sendMessage(msg);
          }
        }
 else {
          player.sendMessage(ChatColor.RED + "String_Node_Str");
        }
      }
 else {
        player.sendMessage(ChatColor.RED + "String_Node_Str");
      }
    }
 else {
      player.sendMessage(ChatColor.GRAY + "String_Node_Str");
    }
  }
 else   if (EconomyHandler.useEconomy()) {
    player.sendMessage(MessageUtils.getNoMoneyMessage(Operation.BLACKSMITH_ARMORREPAIR,player));
    return;
  }
}