Creating a new user or modifying any existing user through MDM GUI may cause a Remote excpetion error with Websphere application server as below.
JAV-8012: Exception (REMOTE EXCEPTION) occurred. Program error or application not installed/configured correctly or application unstable. Contact customer support. Additional information: java.rmi.ServerException: RemoteException occurred in server thread; nested exception is: java.rmi.MarshalException: CORBA MARSHAL 0x4942f8b1 No; nested exception is: org.omg.CORBA.MARSHAL: com.tibco.mdm.directory.security.role.RoleAssignmentElement is not Serializable and not Externalizable vmcid: IBM minor code: 8B1 completed: No, Unknown.