Java EE (Java Enterprise Edition) General Discussion

I am new to Java programming and J2EE platform. Currently I am using JDK1.3.1_01 and J2SDKEE1.3. Just only some days ago, I could properly start up the server and deploy the sample code in J2EE document. But today, when I tried to start the server from the command line, I got several error messages:

J2EE server listen port: 1050
java.lang.RuntimeException: Could not initialize j2ee server. Possible cause could be another instance of the server already running.
at com.sun.enterprise.iiop.POAProtocolMgr.initilizeNaming(POAProtocolMgr.java:134)
at com.sun.enterprise.server.J2EEServer.run(J2EEServer.java:222)
at com.sun.enterprise.server.J2EEServer.main(J2EEServer.java:913)

java.lang.RuntimeException: Could not initialize j2ee server. Possible cause could be another instance of the server already running.
at com.sun.enterprise.iiop.POAProtocolMgr.initilizeNaming(POAProtocolMgr.java:134)
at com.sun.enterprise.server.J2EEServer.run(J2EEServer.java:222)
at com.sun.enterprise.server.J2EEServer.main(J2EEServer.java:913)

java.lang.RuntimeException: Could not initialize j2ee server. Possible cause could be another instance of the server already running.
at com.sun.enterprise.server.J2EEServer.run(J2EEServer.java:350)
at com.sun.enterprise.server.J2EEServer.main(J2EEServer.java:913)

J2EE Server reported the following error: Could not initialize j2ee server. Possible cause could be another instance of the server already running.
Error executing J2EE server ....


By the way, when I try to stop the server using j2ee.bat -stop, I got the following messages:

javax.naming.CommunicationException: Can't find SerialContextProvider
at com.sun.enterprise.naming.SerialContext.getProvider(SerialContext.java:66)
at com.sun.enterprise.naming.SerialContext.lookup(SerialContext.java:154)
at javax.naming.InitialContext.lookup(InitialContext.java:350)
at com.sun.enterprise.util.Utility.lookupObject(Utility.java:122)
at com.sun.enterprise.server.J2EEServer.shutdown(J2EEServer.java:788)
at com.sun.enterprise.server.J2EEServer.main(J2EEServer.java:876)
javax.naming.CommunicationException: Can't find SerialContextProvider
at com.sun.enterprise.naming.SerialContext.getProvider(SerialContext.java:66)
at com.sun.enterprise.naming.SerialContext.lookup(SerialContext.java:154)
at javax.naming.InitialContext.lookup(InitialContext.java:350)
at com.sun.enterprise.util.Utility.lookupObject(Utility.java:122)
at com.sun.enterprise.server.J2EEServer.shutdown(J2EEServer.java:788)
at com.sun.enterprise.server.J2EEServer.main(J2EEServer.java:876)

Unable to shutdown the J2EE server.


I even restarted the PC and tried several times but nothing changed.
Please tell me what was happened and what I should do to solve the problem.

Thank you very much.