I have successfully instaled Apache Tomcat. I also installed an admin package by the following way:
1.copy apache-tomcat-5.5.27\conf\Catalina\localhost\admin.xml to Tomcat 5.5\conf\Catalina\localhost
2.copy apache-tomcat-5.5.27\server\webapps\admin to Tomcat 5.5\webapps
I got an error The requested resource (/admin/) is not available when I tried to open tomcat web adimistration tool.
The solution: copy apache-tomcat-5.5.27\server\webapps\admin to Tomcat 5.5\server\webapps (instead of Tomcat 5.5\webapps
Launch an administration console with http://localhost:8080/admin/.
