Solution : https://service.sap.com/sap/support/notes/534880 (SAP Service marketplace login required)
Key words :
/sapapo/ctm_lc_rfc_write function module, ctm planning run, terms /sapapo/ctm, symptom error messages, /sapapo/ctmmsgoptional, ctm orders, error message, program error, livecache orders, log reason