Solution : https://service.sap.com/sap/support/notes/73662 (SAP Service marketplace login required)
Key words : 
long waiting times occur, additional key words va02, sales information system, order processing, large documents, large number, credit limit, prerequisites customizing, credit check, program error
Related Notes : 
       
| 129470 | Incoming orders for component suppliers: Alternative update | 
| 81335 | Incoming order for sched. agreements not correct |