Hmm, that one I can't answer. I do know, however, that regardless of what CLASSPATH environment settings you have, Tomcat automatically loads any JAR files that it finds under common/lib. Like the Servlet API (servlet.jar) the XML parsing libs, etc. If somehow one of the boxes is picking up tools.jar via the system or user environment classpath, then you wouldn't have to copy it into the common/lib directory. But my attempts last night to just add the path to tools.jar to my CLASSPATH variables didn't yield successful JSP compilation, I had to copy it into common/lib. That tells me that Tomcat is basically ignoring my CLASSPATH settings and using some other mechanism for defining the class path. Haven't read enough to find out what that mechanism is, though.