This can help you.
Index: /trunk/Game/java/net/sf/l2j/gameserver/clientpackets/AddTradeItem.java
===================================================================
--- /trunk/Game/java/net/sf/l2j/gameserver/clientpackets/AddTradeItem.java (revision 8)
+++ /trunk/Game/java/net/sf/l2j/gameserver/clientpackets/AddTradeItem.java (revision 150)
@@ -80,4 +80,10 @@
}
+ if (trade.isConfirmed() || trade.getPartner().getActiveTradeList().isConfirmed())
+ {
+ player.sendMessage("You may no longer adjust items in the trade because the trade has been confirmed.");
+ return;
+ }
+
if (Config.GM_DISABLE_TRANSACTION && player.getAccessLevel() >= Config.GM_TRANSACTION_MIN
&& player.getAccessLevel() <= Config.GM_TRANSACTION_MAX)