If you perform a system restore from image software such as Ghost, the NPS-APACHE.CONF file could become truncated in the process. (located in sys:\tomcat4\conf.)
If this file is truncated to NPS-APACHE~1.CON or some other corrupt filename, rename the file and then stop and restart Apache and Tomcat. For information about restarting Tomcat and Apache, see Starting and Stopping Tomcat and Apache.