Thanks all. FInally, I use JSDK1.4 with Tomcat, then Tomcat works.
SOrry for the unclear thing in my previous post. I did use upper cases for JAVA_HOME and TOMCAT_HOME, and start Tomcat by Startup.
The reason why I choose JDK1.2 is because: I use it to compile my applet, if I use JSDK1.4 to complie my applet, it can not run in IE, so I have to choshose low version JDK. On Tomcat website, they have doc about TOmcat 4.0, but not 4.1, so I assume Tomcat4.1 worked with
Next I will configure TOmcat with IIS. see you soon for my next problems