Solution : https://service.sap.com/sap/support/notes/307496 (SAP Service marketplace login required)
Key words :
//sapserv3/general/r3server/abap/note, symptom plant maintenance orders, additional key words riarcorv, sapserve correction release 4, function module order_change_for_activity, additional code, order network, order networks, prerequisites, hierarchies
Related Notes :
334111 | Archiving PM-relevant data; Sapserv for 4.0B |
208927 | Archiving PM-relevant data |