Create a new database with demo data, load purchases module (or any other module that brings in product data), go to products and export some products with the fields name, default_code and seller_ids. If you try to import the file in question, you will get an error.
This can be reproduced with the following:
Create a new database with demo data, load purchases module (or any other module that brings in product data), go to products and export some products with the fields name, default_code and seller_ids. If you try to import the file in question, you will get an error.