Solution : https://service.sap.com/sap/support/notes/61249 (SAP Service marketplace login required)
Key words : 
prerequisites program error solution source code corrections, additional key words cn21, update termination occurs, entries apparently changed, function module co_vb_change_document_close, function 'reserv, /preq activate', exception sapsql_array_insert_duprec, correspond
Related Notes : 
       
| 71537 | No PReq if required entry fields not filled in PReq |