using iiop with wlclient jar

Hi 

We have an application deployed in a cluster of 3 weblogic 8.1 servers sp3. When
we access the server using the http protocol everything works fine, if we use
the iiop protocol using the wlclient.jar it throws this exception. Could anyone
please say why this would happen.

2007-11-19 12:55:14,903 ERROR [javawsApplicationMain] adm.AdmSessionJ2EE
(AdmSessionJ2EE.java:51) - CORBA COMM_FAILURE 1398079689 No; nested exception
is: 

      org.omg.CORBA.COMM_FAILURE:   vmcid: SUN  minor code: 201  completed: No

java.rmi.MarshalException: CORBA COMM_FAILURE 1398079689 No; nested exception
is: 

      org.omg.CORBA.COMM_FAILURE:   vmcid: SUN  minor code: 201  completed: No

      at
com.sun.corba.se.internal.iiop.ShutdownUtilDelegate.mapSystemException(Unknown
Source)

      at javax.rmi.CORBA.Util.mapSystemException(Unknown Source)

      at com.comp.hlife.client.adm._AdmSessionRemote_Stub.getRole(Unknown S