Solution : https://service.sap.com/sap/support/notes/70932 (SAP Service marketplace login required)
Key words : 
post install/upgrade steps start, post install/upgrade steps, terms post installation upgrade, post processing steps, post processing completed, 3-character system id, cd directory '/qopt', local cd drive, rowan shaw                rowan, shaw@sap-ag
Related Notes : 
       
| 102039 | INST: AS/400: Installing 3-tier systems Rel. 3.1I | 
| 82728 | AS/400: Installing 3.1G on OS/400 V4R1M0 | 
| 68727 | Additional Info: Upgrading to 3.1G DB2/400 | 
| 68259 | AS/400: OS/400-relevant changes from V3R7M0 |