DISPLAY not set

[marist89]

set the DISPLAY environment variable to yourhost:0. For example (assuming /bin/ksh):

workstation1% echo $DISPLAY
:0
workstation1% xhost +
workstation1% rlogin -l oracle server1
password: *********
oracle@server1> export DISPLAY=workstation1:0
oracle@server1> /cdrom/runInstaller