Solution : https://service.sap.com/sap/support/notes/515080 (SAP Service marketplace login required)
Key words : 
runtime error         dbif_rsql_key_not_found  exception               cx_sy_open_sql_dbon, svrmgrl/sqlplus database directly, nt/w2k environment reduces, importing support packages terminates, import support packages, job -> check statuses, profile parameter reason, oracle sga sizes, oracle parameter settings, shared_pool_size    shared_pool_reserved_size    db_block_buffersmay
Related Notes : 
       
| 712624 | High CPU consumption by Oracle | 
| 556764 | Upgrade hangs in phase ACT_<REL> | 
| 521264 | Hang situations | 
| 505246 | Several ora-600 [12333] and ora-4031 errors | 
| 502782 | Composite SAP Note ora-4030 | 
| 442332 | SAPKU30006: Support Package 6 for EBP 3.0/CRM 3.0 | 
| 362068 | Supplement to Oracle migration/upgrade to 8.1.7: UNIX |