This is caused by having an item that was imported from QB, then moved in the hierarchy or deleted from QB.
To fix this error:
- Go to the item in ServiceLedger, make sure it is the correct item by analyzing the items it comes from
- Set the parent item to blank by simply using the backspace key.
- Press <cntrl><alt><z>, look for the link_1 and link_2 fields. Clear them both. Make no other changes and close the administrative window
- Save the item
- Export your invoice
- You will notice your item now exists in QB if no other items caused an error, at the top level
- You can move this item in QB to another parent and re-import your item list to sync the heirarchy with sl. Notice you will need to be in "single-user" mode.
If you delete an item in QB, be sure to try to delete it first in SL. SL knows if it has used it, and the link will fail if you use that item, and it was removed from QB. In this case perform the same steps above, and the item should be recreated.