Here you go, this makes them not able to attack if they are wielding or have the item:
Add it to attackPlayer() in combatassistant.javaif (c.playerEquipment[c.playerWeapon] == #####) {
c.sendMessage("You can't attack with this item!");
return;
}
if (c.getItems().playerHasItem(#####, 1)) {
c.sendMessage("You have an item with you that you can not attack with.");
return;
}