在哪可以下载mod_webapp.so文件?

you can download in the follow homepage
http://jakarta.apache.org/builds/jakarta-tomcat-4.0/release/v4.1.12/src/

and then
http://www.pubbitch.org/jboss.html

修改hosts文件

localhost  127.0.0.1

mod_webapp is now outdated. Please consider using apache with mod_jk2. 
http://www.pubbitch.org/jboss/mod_jk2.html

mod_webapp不支持win32系统
http://www.mail-archive.com/tomcat-dev%40jakarta.apache.org/msg26335.html

if you download jakarta-tomcat-connectors-4.1.12-src.zip
you can find howto configration for win32 in the follow
jakarta-tomcat-connectors-4.1.12-srcjkdocmod_jk-howto.html

you can download binaray of mod_jk2 in the follow
http://jakarta.apache.org/builds/jakarta-tomcat-connectors/jk2/release/v2.0.1/bin/win32/

tomcat 4.1 already have follow files
so you need not to compile it from source
tomcat-jk.jar
tomcat-jk2.jar
tomcat-jini.jar
tomcat-warp.jar