We can use the below code to Submit the Item Import Program using API.

Code is tested in 11i.


 CREATE OR REPLACE PROCEDURE Item_import
 IS

 v_phase               VARCHAR2(240);
 v_status              VARCHAR2(240);
 v_request_phase   VARCHAR2(240);
 v_request_status  VARCHAR2(240);
 v_finished            BOOLEAN;
 v_message          VARCHAR2(240);
 l_request_id         NUMBER;

 BEGIN
 
          Apps Initialize;

      l_request_id := Fnd_Request.submit_request (
                                application   => 'INV',
                               program        => 'INCOIN',
                              description     => NULL,
                              start_time      => SYSDATE,
                              sub_request   => FALSE,
                              argument1     => 1,     --Mode to run this request(Insert new cost information only)
                              argument2     => 1,     --Group ID option (All)
                              argument3     => 1,     -- Group ID Dummy
                             argument4     => 1,
                             argument5     => 1,
                             argument6     => <Group ID>,     -- Group ID passed in Interface table
                             argument7     => <1 or 2>          -- 1 for Create and 2 for Update
                       );                  
      COMMIT;
    
      IF  ( l_request_id = 0 ) THEN
         dbms_output.put_line( 'Submission of Import failed ');
      END IF;
      -- Wait for request to run the import Program to Finish
      v_finished := fnd_concurrent.wait_for_request (request_id      => l_request_id,
                                                     interval        => 60,
                                                     max_wait      => 0,
                                                     phase          => v_phase,
                                                     status          => v_status,
                                                     dev_phase    => v_request_phase,
                                                     dev_status   => v_request_status,
                                                     message      => v_message);

      dbms_output.put_line('Request Phase : '|| v_request_phase );
      dbms_output.put_line('Request Status : ' || v_request_status );

      --Testing end status
      IF ( UPPER(v_request_status) = 'NORMAL') THEN
          dbms_output.put_line( 'Submission of Item Import is Success ');
      ELSE
          dbms_output.put_line( 'Submission of Item Import failed ');
      END IF;
    
 EXCEPTION
    WHEN OTHERS THEN
         dbms_output.put_line( 'Submission of Import failed ');
 END ;
 /