using the Vendor Invoice entities fails for import

Hi,

I exported a data package (using the 8.1-developer VM) with a "Pending Vendor Invoice" using the "data management".

I used the entities:

- Vendor invoice header

- Vendor invoice line

- Vendor invoice document attachment

When I try to use this entities for import (using the exported data package), the header works fine, but the lines produce the following error.

Any hints why I get the validation-errors for the BudgetReservationHeader_PSN?

Thanks in advance.

Sascha Storzum