Whenever Administration Console reports a 500 internal error, the reason for failure is included in the response and visible on the browser. This might cause a security issue.
To prevent this, add the following valve in the server.xml file:
Linux: /opt/novell/nam/adminconsole/conf
Windows Server 2012: \Program Files (x86)\Novell\Tomcat\conf
<Valve className="org.apache.catalina.valves.ErrorReportValve" showReport="false" showServerInfo="false"/>