Solution : https://service.sap.com/sap/support/notes/661525 (SAP Service marketplace login required)
Key words :
abap runtime error uc_objects_not_convertible, archiving object sd_vbak, terms insert_obj_data_from_archive reason, reload documents, data objects, unicode programs, source code, unicode-compatible, attached corrections, convertible
Related Notes :
373568 | Archiving SD: Reloading documents not supported |
198508 | Missing database COMMIT in reload program |