Solution : https://service.sap.com/sap/support/notes/602759 (SAP Service marketplace login required)
Key words : 
attached correction instructions, error message c0 820, internal error, program error, bapi bapi_alm_order_maintain, process maintenance, service orders, dump not_found, bapi terminates, terms bapi
Related Notes : 
       
| 736204 | Notes for downgrade kit ALMBAPI I | 
| 708508 | Downgrade BAPI_ALM_ORDER_MAINTAIN -> errors |