Function TO_NUMBER not working after DB upgrade.

Hi All,

We have a custom table, where the column "transaction Amount" is of type VARCHAR2(30).
The data into this custom table is populated through the data file for this column value in the data file is 000000000234.00

The Concurrent Program executable is based on this package which validates amount column data using below query :
               BEGIN
           SELECT TO_NUMBER (p_in_num_trx_amt)
             INTO l_num_amt
             FROM DUAL;
        EXCEPTION
           WHEN OTHERS
           THEN
              l_chr_err_msg :=
                        SQLERRM||'ERROR:Transaction Amount Should have numeric value';
              l_chr_err_code := '002';        
              l_chr_err_stg :=
                            l_chr_err_stg || '@' || 'TRANSACTION_AMOUNT-002' || '-' || p_in_num_trx_amt;