Solution : https://service.sap.com/sap/support/notes/547248 (SAP Service marketplace login required)
Key words :
extended withholding tax reason, extended withholding tax functionality, table field with_item-j_1irebzg, table with_item field rebzg, country version india, prerequisites upgrade modification, table with_item, field rebzg, field rebzg, fields j_1irebzg