Solution : https://service.sap.com/sap/support/notes/747622 (SAP Service marketplace login required)
Key words : 
terms sap erp central component 5, sap erp central component 5, sap srm server 5, 'sqldb_cvers_act_corr' upgrade phase, r3up6401 patch 2 reason, 'component' field, 'sap_bw' component, r3up6401 patch #2, xpra phase, 'active' field
Related Notes : 
       
| 788218 | Add. info. on upgrading to SAP ERP Central Component 5.0 SR1 | 
| 705578 | Additions to upgrade on SAP SRM Server 5.0 | 
| 689574 | Add. info. on upgrading to SAP ERP Central Component 5.00 | 
| 663258 | Corrections for R3up version 640 |