'Requisition Import program' creates interface line errors

We have created an item which is eligible for ‘Back to back order’ type sales orders.

Once the sales order progressed, status changed in to ‘External Req Requested’.

Then we submit the ‘Requisition Import’ program. System didn’t create any requisitions from the import program.

From the ‘Requisition import exception report’ following output was created.

“Cause: You entered an item that is invalid or not purchasing-enabled for the destination organization. This is required for a source type of’ Supplier'.

Action: Enter a valid item that is purchasing-enabled for the destination organization.”

Purchasing attributes are already available for this item.

How to fix the issue and generate a requisition from the ‘Requisition import program?