Try the command echo $PATH

Mine looks like this:

$ echo $PATH
/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/X11R6/bin:/usr/games:/usr/sbin:/usr/java/jre1.3.1_02/bin

If java isn't set in your $PATH it won't run.

Edit the .bashrc file thus:
# .bashrc

# User specific aliases and functions

# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi


PATH=/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/X11R6/bin:/usr/games:/usr/sbin:/usr/java/jre1.3.1_02/bin

==========

So simply add /usr/java/jre1.3.1_02/bin

Note the colons separating each path!