Solution : https://service.sap.com/sap/support/notes/624393 (SAP Service marketplace login required)
Key words : 
terms sap internet sales, order status reason, internet user, sales orders, sales documents, symptom due, technical problem, b2c scenario, program error, patch prevents
Related Notes : 
       
| 646140 | Security Check of Internet Sales | 
| 625135 | CRM ABAP solution: Display orders of other users possible | 
| 569482 |