[ns] NAM : NO DISPLAY NAME AND NO $DISPLAY ENVIRONMENT VARIABLE

[Bety Barreto Soares]

still in the same example myfirst_ns.tcl, i have changed and do some change but 
when run it showed that :

NAM : NO DISPLAY NAME AND NO $DISPLAY ENVIRONMENT VARIABLE


I HAVE BROWSED ON THE INTERNET BUT I GOT NO SOLUTION...PLEASE HELP ME OUT

THANK YOU