Resolution:
If you are running a "headless" Unix machine without X11 installed, you may have difficulty starting the Manager, and you won't be able to display a graph or chart in the Administration Tool.

If you're using Java 1.4, edit the last line of server.sh to include the argument

-J-Djava.awt.headless=true

You can also use xvfb, which is included with the standard X11R6 distribution, to run a virtual X Server on a machine with no display hardware.