this seems like a classpath type conflict. Make sure the classpath isn't set with any extra jars before you start jboss. Set JAVA_HOME and thats it. Jboss startup scripts should do the rest.
I had tried some classpath variations but as you suggest, I deleted the classpath entry in my XP user account. Then tried the JBoss run.bat. At the beginning of the log file, a class path is generated of:
(the odd "C:\PROGRA~1\JDK13~1.1_0" was required to avoid embedded spaces in the path name).
This still generated the Catalina errors.
Elsewhere in this forum I found another reference:
http://www.jboss.org/modules/bb/index.html?module=bb&op=viewtopic&t=forums/ reference talks about a CATALINA_HOME environmental variable. After discussing it with the teacher of the class, I made the following changes:
Created an environmental variable in my XP user account of CATALINA_HOME=C:\java\jboss-3.0\catalina
Then edited the tomcat4-service.xml file to fully specify the path, changing the line
<!ENTITY catalina.home "../catalina">
<!ENTITY catalina.home "C:/java/jboss-3.0/catalina">
I then ran the JBoss run.bat file. None of the catalina errors occurred. I've stopped and started JBoss several times and the errors have not returned. I've tested it with a JSP page and it works. I also rebooted once and restarted it, once again with no catalina errors. I don't know why this should solve the problem but it's running so far. Thanks for your suggestion anyway.
This looks just a relative path problem.
I guess you started jboss not from %JBOSS_HOME%\bin.
Change directory to %JBOSS_HOME%\bin, then type run.bat.