Solution : https://service.sap.com/sap/support/notes/446485 (SAP Service marketplace login required)
Summary : 
      
Key words : 
copying classes including client import postprocessing, no_rfcchk - ignoring rfc repository check 12, no_rfcchk - ignoring rfc repository check, system-wide exclusive locks<z1> 10, system-wide exclusive locks<z1>, message ta 390                        code page conversion, sap web application server release 6, chk_assign - extended consistency check, system-wide exclusive locks, conversion errors occur due
Related Notes : 
       
| 937934 | CC-ADMIN : Buffer reset option in SCC1 | 
| 898228 | CC-Error: Remote copy with active option IGNORE_CONV aborts | 
| 784442 | CC-ADMIN: New NO_CHECK option for runtime optimization | 
| 697445 | Abnormal termination with client copy | 
| 691508 | CC-ERROR: DBIF_DSQL2_SQL_ERROR with option 390OPT | 
| 579783 | CC ERROR: Loss of data - table not copied | 
| 562628 | CC-ADMIN: Protecting the source from a second copy | 
| 557132 | CC-TOPIC: Remote client copy | 
| 517589 | iSeries: Client copy performance | 
| 491923 | CC RELEASE: Client copy errors in Release 6.20 | 
| 489690 | CC INFO: Copying large production clients | 
| 432152 | CC-RELEASE: Error in client copy in Release 6.10 | 
| 365304 | CC-ADMIN: Reports for deleting tables | 
| 67205 | CC-INFO: Copying large and productive clients | 
| 24853 | CC-INFO: Client copy, functionality | 
| 22514 | CC-INFO: Error analysis for client copy |