To resolve the error, remove the Tag along item from the item's Special tab, or select a Tag along item which is in stock.
1. In Store Operations Manager, select Database, Items and open the item generating the error.
2. Select the Special tab.
3. To remove the Tag along item selected, click the red X button next to the item, then click OK to save the change.
4. To select a different Tag along item which is in stock, click the magnifying glass icon next to the Tag along item field and select another item, then click OK to save the change.