Solution : https://service.sap.com/sap/support/notes/620253 (SAP Service marketplace login required)
Key words : 
uc_objects_not_convertible runtime error occurs, automatic change recording, subsequent after_imp_cust_address processing, bc-srv-adr, relevant address data, attached correction instructions, error occurs, correction instructions, error message, 'database error
Related Notes : 
       
| 1319517 | Unicode Collection Note | 
| 638357 | Transport between Unicode systems and non-Unicode systems | 
| 385440 | Repairing inconsistencies in Customizing addresses |