On your desktop, right click on "My Computer" select "Properties"
under the environment variable settings, create a new variable called JAVA_HOME and have it point to your java installation
this doc explains it

Namaste - I bow to the divine in you
Filip Hanik
Software Architect

-----Original Message-----
From: Manish Pradhan [mailto:manishp@vsnl.com]
Sent: Thursday, July 19, 2001 10:56 AM
To: tomcat-user@jakarta.apache.org
Subject: Unable to start tomcat server

Kindly explain to me how to configure java_home or tomcat_home property.Because everytime ,I go tostart the tomcat webserver 3.2.2 on my windows 98 system & click on start up.bat there is a message"you must set JAVA_HOME to point at your Java Development Kit Installation.Kindly oblige.