Solution : https://service.sap.com/sap/support/notes/50708 (SAP Service marketplace login required)
Key words : 
error message rw022 'fi/, statistical order/wbs element, prerequisites program error, line item header, additional key words, multiple account assignment, group asset assignment, wbs element, purchase order, account assignment
Related Notes : 
       
| 68839 | Settlement to fixed asset with group assets->RW022 |