The instructions in this section instruct you to edit the context.xml file to override Tomcat default settings. Your application server may not support this method, or may not accept these files by default. This will be especially true if you are using unsupported application servers or versions, or if you are on Linux and your distribution provider alters the default package configuration for Tomcat.
There are other methods of changing context settings, especially through other kinds of configuration files such as server.xml or application-specific XML files that your application server creates for each deployed WAR. If the context and data source instructions in this section do not work for you, consult your application server's documentation to learn the preferred method of configuration, and adapt the Pentaho-supplied process to accommodate it.