Did you install Tomcat administration web application for Tomcat 6.0.x ? When I browse http://myserver:8080/admin/, it says "Tomcat's administration web application is no longer installed by default. Download and install the "admin" package to use it.", but I couldn't found where I can download it.
The Administration Web Application tools is only available until Tomcat 5.5.28. Try to download the Admin Tool and extract it. After extracting the package, copy the \apache-tomcat-5.5.28\conf\Catalina\localhost\admin.xml to $CATALINA_HOME\localhost.
Next, copy the \apache-tomcat-5.5.28\server\webapps\admin directory to $CATALINA_HOME\server\webapps
I hope this gonna work.