Tomcat start up error

I am getting the following error in the Catalina log file while starting Tomcat on Windows:

Sep 3, 2010 3:22:53 PM org.apache.catalina.startup.Catalina start
SEVERE: Catalina.start: 
LifecycleException:  service.getName(): "Catalina";  Protocol handler start failed: java.lang.Exception: Socket bind failed: [730048] Only one usage of each socket address (protocol/network address/port) is normally permitted.  
    at org.apache.catalina.connector.Connector.start(Connector.java:1138)
    at org.apache.catalina.core.StandardService.start(StandardService.java:531)
    at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Sep 3, 2010 3:22:53 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 67604 ms

But when I changed the port number from 8080 to 9000 then there was no error but the request to http://localhost:9000/ gives the 404 error The requested resource (/) is not available.

Am I missing something?