Solution : https://service.sap.com/sap/support/notes/766271 (SAP Service marketplace login required)
Key words : 
external unicode server terminates, terms rfc library reason, sar-patch-level  7 release 6, sar-patch-level 72, unicode rfc library, rfc_conversion return code, rfc library, ifthe server, patch number 33, patch number 1677
Related Notes : 
       
| 766807 | RFC Patch Collection 35 2004 | 
| 766120 | CCMS connection problems after database upgrade/migration |