How to enable the Default Operating Unit in R12

1. Login into application with System Administration responsibility after then  Concurrent -> Programs

2. Query for short name of the concurrent program to find and then click update button.

3. Select on Request Tab.

4. Select Single from the drop down of Operating Unit Mode field.

5. Save changes by clicking on Apply button 

How to Create the Value Set via Script

BEGIN
   FND_FLEX_VAL_API.SET_SESSION_MODE ('customer_data');          /*Mandatory*/
   FND_FLEX_VAL_API.CREATE_VALUESET_TABLE (
      VALUE_SET_NAME            => 'XXCONA_REQ_NO_VS',
      DESCRIPTION               => 'XXCONA Requisition Number',
      SECURITY_AVAILABLE        => 'N',
      ENABLE_LONGLIST           => 'N',
      FORMAT_TYPE               => 'Char',
      MAXIMUM_SIZE              => 20,
      PRECISION                 => NULL,
      NUMBERS_ONLY              => 'N',
      UPPERCASE_ONLY            => 'N',
      RIGHT_JUSTIFY_ZERO_FILL   => 'N',
      MIN_VALUE                 => NULL,
      MAX_VALUE                 => NULL,
      TABLE_APPLICATION         => 'Purchasing',
      table_appl_short_name     => 'PO',
      TABLE_NAME                => 'PO_REQUISITION_HEADERS',
      ALLOW_PARENT_VALUES       => 'N',
      VALUE_COLUMN_NAME         => 'SEGMENT1',
      VALUE_COLUMN_TYPE         => 'Char',
      VALUE_COLUMN_SIZE         => 20,
      MEANING_COLUMN_NAME       => NULL,
      MEANING_COLUMN_TYPE       => NULL,
      MEANING_COLUMN_SIZE       => NULL,
      ID_COLUMN_NAME            => NULL,
      ID_COLUMN_TYPE            => NULL,
      ID_COLUMN_SIZE            => NULL,
      WHERE_ORDER_BY            => 'WHERE org_id = mo_global.get_current_org_id ORDER BY segment1 DESC',
      ADDITIONAL_COLUMNS        => NULL
   );
   COMMIT;
EXCEPTION
   WHEN OTHERS
   THEN
      DBMS_OUTPUT.put_line (SQLERRM);
END;

end;