Linux can not open display

[jos]

Linux can not open display:

I installed the Apps 11i in the RedHat Linux AS4. Now I am facing a problem.

The reason I was tries to apply ?ssh? from the telnet and the node.

But I can use telnet to logon the Linux from another PC with any user.

Now there is a problem while booting I cannot logon from the login prompt. After apply username and password it gives an Error message. Then press this View details

[] View details (-/.xsession ? error file)

etc/x11/gdm/presession/Default: Registering your session with wtmp and utmp
etc/x11/gdm/presession/Default: running: /usr/bin/x11/sessreg ?a ?w /var/log/wtmp ?u /var/rm/utmp ?x ?/var/gdm/:0.Xservers? ?-l? ?-l? ?:0? ?root?

(gnome-session:12136):
gtk-WARNING **: can not open display.

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I can logon with
* Failsafe Terminal . (logon by root)

Now how I can solve the problem?