Problems in setting display variable for X Windows server

[santhosh]

Hi ,
       I have some problems in setting the display variable for X windows.
Things were working fine when I wanted to change the hostname of my server.
I did all the necessary changes in the files:
1.	/etc/hosts
2.	/etc/sysconfig/network
3.	/proc/sys/kernel/hostname
4.	/etc/sysconfig/network-scripts

 Then I wanted to revert back to my old settings, I undid all the changes.
Now the responses for few commands to set my display variable are like this;

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   [root at localhost root]# echo $DSIPLAY
        (blank)
[root at localhost root]#

even after I give the command export DISPLAY=localhost:0
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[root at localhost root]#xterm
Xlib: connection to "localhost:0.0" refused by server
Xlib: Client is not authorized to connect to Server
Warning: This program is an suid-root 




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[root at localhost root]# xhost
Xlib: connection to "localhost:0.0" refused by server
Xlib: Client is not authorized to connect to Server
xhost:  unable to open display "localhost:0"

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[root at localhost root]# xinit

Fatal server error:
Server is already active for display 0
        If this server is no longer running, remove /tmp/.X0-lock
        and start again.

When reporting a problem related to a server crash, please send
the full server output, not just the last messages.
Please report problems to xfree86 at xfree86.org.

Xlib: connection to ":0.0" refused by server
Xlib: Client is not authorized to connect to Server
giving up.
xinit:  unable to connect to X server
xinit:  No such process (errno 3):  Server error.
[root at localhost root]#
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Though , I should say I am a newbie
..to Linux environment, and much of an
application development guy
facing problems in displaying graphics in my
servlet.

Please help me.

Regards
Santhosh