The page you tried to access does not exist.
The Manager application has been re-structured for Tomcat 7 onwards and some of URLs have changed. All URLs used to access the Manager application should now start with one of the following options:
Note that the URL for the text interface has changed from "www.52mse.com" to "www.52mse.com/text".
You probably need to adjust the URL you are using to access the Manager application. However, there is always a chance you have found a bug in the Manager application. If you are sure you have found a bug, and that the bug has not already been reported, please report it to the Apache Tomcat team.