ORACLE/PLSQL: ORA-04091

I have a package that include a procedure as I try to exec as bellow:

begin

tahs_aktarim_.tahs_aktarim('45397','T1' );

end;

I try to insert data to ps_Acu_sf_tahs table and I m getting error.

/* Formatted on 28.12.2015 14:04:34 (QP5 v5.149.1003.31008) */

CREATE OR REPLACE PACKAGE BODY tahs_aktarim_

AS

   FUNCTION taksit_bul (f_national_id CHAR)

      RETURN CHAR

   IS

      v_yeni_debit_taksit   CHAR;

   BEGIN

      SELECT CASE

                WHEN (  SELECT LPAD (NVL (COUNT (*) + 1, 0), 2, 0)

                          FROM ps_acu_sf_tahs k

                         WHERE (emplid, acad_career, stdnt_car_nbr, acad_prog) IN

                                  (SELECT emplid,

                                          acad_career,

                                          stdnt_car_nbr,

                                          acad_prog

                                     FROM ps_acu_stu_info a, ps_acu_tahs b

                                    WHERE     a.national_id = f_national_id

                                          AND a.national_id = b.national_id

                                          AND k.emplid = a.emplid)

                               AND acu_debit_term =

                                      (SELECT acu_debit_term

                                         FROM ps_tahs_kriter)

                               AND acu_payment_term =

                                      (SELECT acu_payment_term

                                         FROM ps_tahs_kriter)

                      GROUP BY emplid,

                               acad_career,

                               stdnt_car_nbr,

                               acad_prog,

                               acu_debit_term,

                               acu_debit_type,

                               acu_payment_term)

                        IS NULL

                THEN

                   '01'

                ELSE

                   (  SELECT LPAD (NVL (COUNT (*) + 1, 0), 2, 0)

                        FROM ps_acu_sf_tahs k

                       WHERE (emplid, acad_career, stdnt_car_nbr, acad_prog) IN

                                (SELECT emplid,

                                        acad_career,

                                        stdnt_car_nbr,

                                        acad_prog

                                   FROM ps_acu_stu_info a, ps_acu_tahs b

                                  WHERE     a.national_id = f_national_id

                                        AND a.national_id = b.national_id

                                        AND k.emplid = a.emplid)

                             AND acu_debit_term =

                                    (SELECT acu_debit_term FROM ps_tahs_kriter)

                             AND acu_payment_term =

                                    (SELECT acu_payment_term

                                       FROM ps_tahs_kriter)

                    GROUP BY emplid,

                             acad_career,

                             stdnt_car_nbr,

                             acad_prog,

                             acu_debit_term,

                             acu_debit_type,

                             acu_payment_term)

             END

                AS debit_taksit

        INTO v_yeni_debit_taksit

        FROM DUAL;

   END;

   PROCEDURE tahs_aktarim (p_national_id CHAR, p_flag CHAR)

   IS

      nid                   NUMBER;

      v_emplid              NUMBER;

      v_acu_debit_term      VARCHAR2 (4 CHAR);

      v_acu_payment_term    VARCHAR2 (1 CHAR);

      v_currency_cd         VARCHAR2 (10 CHAR);

      v_acu_kur             NUMBER;

      v_acu_payment_typ     VARCHAR2 (5 CHAR);

      v_acu_flag            VARCHAR2 (5 CHAR);

      v_comments            VARCHAR2 (300 CHAR);

      v_bank_cd             VARCHAR2 (2);

      v_branch_ec_cd        VARCHAR2 (50);

      v_account_num         VARCHAR2 (50 CHAR);

      v_acu_debit_taksit    VARCHAR2 (3 CHAR);

      v_acu_debit_type      VARCHAR2 (5 CHAR);

      v_oprid               VARCHAR2 (50 CHAR);

      v_total_receivable    NUMBER;

      v_tahsilat_tutari     NUMBER;

      v_tahs_tarih          NUMBER;

      v_banka_odeme_sekli   VARCHAR (2 CHAR);     --P0, P1, T1, T2...

      v_yeni_debit_taksit   VARCHAR (20 CHAR);

      v_amount              NUMBER;

      v_updated             DATE;

   BEGIN

      /*criterion of receipt*/

      SELECT acu_debit_term,

             acu_payment_term,

             DECODE (currency_cd, 'TL', 'TRY', currency_cd),

             acu_kur,

             acu_payment_typ,

             acu_flag,

             comments,

             bank_cd,

             branch_ec_cd,

             account_num,

             acu_debit_taksit,

             acu_debit_type,

             oprid

        INTO v_acu_debit_term,

             v_acu_payment_term,

             v_currency_cd,

             v_acu_kur,

             v_acu_payment_typ,

             v_acu_flag,

             v_comments,

             v_bank_cd,

             v_branch_ec_cd,

             v_account_num,

             v_acu_debit_taksit,

             v_acu_debit_type,

             v_oprid

        FROM ps_tahs_kriter;

      /*count of total receipt based on payment type*/

      --select count(*) into v_total_receivable from ps_acu_tahs where national_id=p_national_id;

      /*receipt information of students*/

      SELECT amount, updated, acu_flag3

        INTO v_tahsilat_tutari, v_tahs_tarih, v_banka_odeme_sekli

        FROM ps_acu_tahs

       WHERE national_id = p_national_id;

      /*students' emplid*/

      SELECT emplid

        INTO v_emplid

        FROM ps_acu_stu_info

       WHERE national_id = p_national_id;

      IF v_banka_odeme_sekli = 'P1' OR v_banka_odeme_sekli = 'T1'

      THEN

         /*insert receipt information to ps_Acu_sf_tahs table*/  --> SOURCE OF ERROR!!

         INSERT INTO ps_acu_sf_tahs

            SELECT 'ACU',

                   b.emplid,

                   b.acad_career,

                   b.stdnt_car_nbr,

                   b.acad_prog,

                   ps_acu_tahs_sequence.NEXTVAL,

                   TO_DATE (a.updated, 'RRRRMMDD'),

                   v_acu_debit_term,

                   v_acu_debit_type,

                   v_acu_payment_term,

                   taksit_bul (p_national_id),

                   v_acu_payment_typ,

                   a.amount,

                   v_currency_cd,

                   v_acu_kur,

                   a.amount * v_acu_kur,

                   'TUR',

                   v_bank_cd,

                   v_branch_ec_cd,

                   v_account_num,

                   'N',

                   v_oprid,

                   SYSDATE,

                   v_comments

              FROM ps_acu_tahs a, ps_acu_stu_info b

             WHERE     a.national_id = b.national_id

                   AND a.national_id = p_national_id

                   AND acu_flag3 = p_flag

                   AND prog_status IN ('AC', 'LA');

         IF v_banka_odeme_sekli = 'P0'

         THEN

            SELECT amount / 2, updated, acu_flag3

              INTO v_tahsilat_tutari, v_tahs_tarih, v_banka_odeme_sekli

              FROM ps_acu_tahs

             WHERE national_id = p_national_id AND acu_flag3 = p_flag;

            /* insert fall debit amount*/

            INSERT INTO ps_acu_sf_tahs

               SELECT 'ACU',

                      b.emplid,

                      b.acad_career,

                      b.stdnt_car_nbr,

                      b.acad_prog,

                      PS_ACU_TAHS_SEQUENCE.NEXTVAL,

                      TO_DATE (a.updated, 'RRRRMMDD'),

                      v_acu_debit_term,

                      v_acu_debit_type,

                      'G',

                      '01',

                      v_acu_payment_typ,

                      a.amount,

                      v_currency_cd,

                      v_acu_kur,

                      a.amount * v_acu_kur,

                      'TUR',

                      v_bank_cd,

                      v_branch_ec_cd,

                      v_account_num,

                      'N',

                      v_oprid,

                      SYSDATE,

                      v_comments

                 FROM ps_acu_TAHS a, ps_acu_stu_info b

                WHERE     a.national_id = b.national_id

                      AND a.national_id = p_national_id

                      AND prog_status IN ('AC', 'LA');

end tahs_aktarim_;

/