Solution : https://service.sap.com/sap/support/notes/63310 (SAP Service marketplace login required)
Key words : 
additional key words report writer, symptom cost element-oriented reports, cost element reports, ps info system, source code corrections, report painter, table ccss, characteristic posid, prerequisites orders, implement note 51251
Related Notes : 
       
| 81346 | Line item and cost element report authorizations | 
| 76912 | PS cost element reports: Authorization for network | 
| 76310 | Cost element reports: Error in authorization check | 
| 73417 | PS Info System: Authorizat. check for network/order | 
| 51520 | Assignment to order for WBS element is missing | 
| 51251 | No object currency in cost element reports |