You know what....I forgot about that! If I remember correctly, those machines don't have graphics cards. Hmmmmmm.... I am not sure if you will be able to launch those programs or not.
You will be unsucessful through the serial port, but if the machine is on a network, you may be able to use them through another UNIX server or a PC running an X-server client (such as Hummingbird Exceed or Reflections X).
The display varible just tells the OS where to send your "display". For example, if you are on another UNIX box, try this:
rlogin <the netra>
DISPLAY=<the IP of your UNIX box>:0.0
export DISPLAY
/usr/bin/admintool &
If this is successfull, you should see Admintool launched onto your desktop.