my web application's directory is Tomcat 4.1\webapps\mystruts,but i can't compile the UserInfoBo.java file in Tomcat 4.1\webapps\mystruts\WEB-INF\classes\bussness,what should i do?

Where is your UserInfoBo.java located?? If it is not located under \Tomcat4.1\webapps\mystruts\WEB-INF\classes\business directory, then you would need to use the option -d which specify the location of where to plcae the generated class files when compiling the UserInfoBo.java file

Your UserInfoBo.java needs to be deployed as a .class file. Tomcat will not compile .java files for you, it will only compile JSPs on-the-fly.

Jon Emerson
http://www.jonemerson.net/