OK, you need to find out what version of java is on the server

I think the command is:

java -version

if it doesn't match 1.4.2 or higher you need to download a new version from java.com there are two versions download the JRE unless you are planning on developing java apps.

You need to set the java enviroment: create a file named java.sh in /etc/profile.d with the following content:

export JAVA_HOME=/usr/local/java
export PATH=$PATH:$JAVA_HOME/bin
export CLASSPATH=$JAVA_HOME/lib

use the paths to your java install the one above is an example