Error while create temporary clob in Java for call to Oracle stored procedure

I am working with Oracle 9i. From web services written in Java I am calling Oracle stored procedure. As the length of one of the input parameter is more than 32K, I want to pass it as CLOB. I have written following code which gets compiled and build properly but shows the error when run. The error is at the  line filecontentClob = oracle.sql.CLOB.createTemporary(conn, true, oracle.sql.CLOB.DURATION_SESSION);.

Code:
======================

Clob filecontentClob= null;  

try
{          

  conn = getConnection();
  filecontentClob = oracle.sql.CLOB.createTemporary(conn, true, oracle.sql.CLOB.DURATION_SESSION);

   if(filecontentClob!=null) {
      ((oracle.sql.CLOB)filecontentClob).putString(1, fileContent);
    }

   //Make a call to the get_application_status procedure of the API_STL package
   ocstmt = (OracleCallableStatement)(conn.prepareCall("{call API_DWP.DWP_DELIVER_FILE_TO_EMASYS(?,?,?,?)}"));

   ocstmt.setString(1, filename);
   //ocstmt.setString(2, fileContent);   Old call
   ocstmt.setClob(2, filecontentClob);  // New call
   ocstmt.registerOutParameter(3, OracleTypes.INTEGER);
   ocstmt.registerOutParameter(4, OracleTypes.VARCHAR);

   ocstmt.execute();

Error message is as below:
======================
Exception in JSP: com.evermind.server.rmi.OrionRemoteException: java.sql.SQLException: Invalid argument(s) in call; nested exception is: java.sql.SQLException: Invalid argument(s) in call