well the iventory is probably not finished.
the iventory can't be closed, and blocks the whole game.
the documentation is wrong, in the manual it says:
item_DBslot = AddItemToInvDB
("item.img", "item.anm", "item name", itemid, weight,
quantity, "f_look_item", "f_use_item", "f_combine_item")
but quantity isnt mentioned in the sourcecode