
Batch [batch number] in row [item number] already exists
You have tried to create goods receipt PO that includes the item and batch number mentioned in the message as a regular document, but the batch number assigned to the item at the time the draft was created already exists.
Assigning the same batch number to the same item is impossible. Before adding the draft as regular document, press CTRL+TAB in the Quantity column assign different batch number for the item. Then add the document.