If the service installs properly, but fails to start, you can use the steps provided here to troubleshoot.
For additional details on using the Tomcat service and service monitor, see http://tomcat.apache.org/tomcat-6.0-doc/windows-service-howto.html.
As you are troubleshooting, check the log files (endeca-portal\tomcat-6.0.x\logs\jakarta_service*.log) for the relevant messages.
If the service will not start: