Solution : https://service.sap.com/sap/support/notes/318172 (SAP Service marketplace login required)
Key words : 
/ important general remarks-----------------------< d01890  04/sep/00>----------------------------minimum requirement, inconsistency problem 'system cross reference files', /    important general remarks ii/   errors, ------------------------< d021890 07/aug/98>---------------------------phase newtab_cre symptom, upgrade procedure additional key words, ------------------------< d021890 08/jun/98 >-------------------------phase dbchk symptom, note 114028 ------------------------< d022877 19/sep/97 >-------------------------phase pcon_31isymptom, avoids additional disk space, press function key f21, pressing function key f12
Related Notes : 
       
| 428855 | IBM i system values | 
| 380968 | AS/400: Checking table types before the upgrade | 
| 315377 | Additional information about upgrading to 3.1I SR1 |