Tx for the reply.
I did not create those fields, I clicked on download column headers, so they come from VirtueMart.
Here is my problem: I download all products to an XLS spreadsheet, open it, view it and so on.
When I try to upload the very same spreadsheet after adding 1 test product, it gives me the error "product_parent_id not supported",
so I go back and download a new spreadsheet without using column headers, add another product, upload the spreadsheet back and
no new product... It does not add products.
Maybe I am doing something wrong?