Session already invalidated error

hello i am running tomcat and axis on my server, and i am always getting this error in my log files anytime my webapplication and webservice starts...

I dont know what the exception means..does the [/axis] means the error occurs in axis folder of my webapplication?

why is it Session gets invalidated..when there is no session variables created in webservices in my axis folder?

here is the full stacktrace:

2007-01-29 10:46:07 StandardManager[/axis] Session event listener threw exception

java.lang.IllegalStateException: getAttribute: Session already invalidated

at org.apache.catalina.session.StandardSession.getAttribute(StandardSession.java:925)

at org.apache.catalina.session.StandardSessionFacade.getAttribute(StandardSessionFacade.java:124)

at org.apache.axis.transport.http.AxisHTTPSessionListener.destroySession(AxisHTTPSessionListener.java:43)

at org.apache.axis.transport.http.AxisHTTPSessionListener.sessionDestroyed(AxisHTTPSessionListener.java:72)

at org.apache.catalina.session.StandardSession.expire(StandardSession.java:623)

at org.apache.catalina.session.StandardSession.expire(StandardSession.java:572)

at org.apache.catalina.session.StandardManager.processExpires(StandardManager.java:746)

at org.apache.catalina.session.StandardManager.run(StandardManager.java:823)

at java.lang.Thread.run(Thread.java:534)

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i'll be soo much grateful if anyone will help me in trying to solve this problem.. thanks in advance..

[1545 byte] By [rinoa_fftsya] at [2007-11-26 16:29:53]