Problem in adding the User into Portal

Hi Seniors,

 I had a requirement that when ever i register the user in to janu application need to be add the USER into 
PORTAL30(wwsec_person$ Table).

I have searched in Google i found the API (WWSEC_API) of add_portal_user(Function) is this ..?

If soo i have executed this but getting the error ......

SQL> begin
  2  wwctx_api_private.set_context( p_user_name => 'SEENU'
  3      , p_password => 'SEENU');
  4  end;
  5  /

PL/SQL procedure successfully completed.

SQL> 
SQL> declare
  2       l_id number;
  3   begin
  4       l_id := wwsec_api.add_portal_user
  5       (
  6         p_User_Name     => 'SEENU',
  7         p_Empno         => '123-45-6789',
  8         p_Display_Personal_Info  => 'Y',
  9         p_Last_Name     => 'Seenu',
 10         p_First_Name    => 'D',
 11         p_Middle_Name   => 'Janu',
 12         p_Known_As      => 'SeenuJanu',
 13         p_Date_Of_Birth => '15-MAR-1980',
 14         p_Email         => 'seenu@abc.com',
 15         p_Office_City   => 'Chennai',
 16         p_Portal_User   => 'Y'
 17       );
 18   end;
 19  
 20  /
declare
*
ERROR at line 1:
ORA-06510: PL/SQL: unhandled user-defined exception
ORA-06512: at "PORTAL30.WWSEC_API", line 1277
ORA-06512: at line 4

	Thanks in Advance

Regards

Seenu