This error occurs when there is an item on the Purchase Order that has not been entered in your Item Table in Scan and Pack. In order to correct the error, add the missing item/items to your item table. To do so, navigate to Maintenance, then Items, which will bring up a screen with all existing items. Click on New, and add all pertinent item information for the missing/new item(s). After all items are added, close out of your item table, and refresh orders again.