This message could show up in any area of Ostendo. It it usually to do with missing ITEMUNITS records as a result of data being imported incorrectly into Ostendo. To fix this, simply create an import file for the ITEMUNITS table of the missing records.
Run this query to identify the missing records and manually add them.
Select itemmaster.itemcode, itemunits.itemcode from (itemmaster LEFT join itemunits on itemmaster.itemcode = itemunits.itemcode)
where itemunits.itemcode is null
if not results from that, run this query
select inventory.itemcode, itemunits.itemcode from (inventory LEFT join
itemunits on inventory.itemcode || inventory.inventoryunit = itemunits.itemcode || itemunits.tounit)
where itemunits.itemcode is null