Solution : https://service.sap.com/sap/support/notes/806470 (SAP Service marketplace login required)
Key words :
sapgw<system number> <gateway port>/tcpask back-end system administrator, migration edit services filewindows location, back-end system number, nw'04 portalas system administrator, missing gateway port definition, back-end system, proper gateway port, 'gateway host' - usual, symptom java iview, \winnt\system32\drivers\
Related Notes :
732461 | Migration of EP & KM from 5.0 to NW '04 - Central Note |