Date Problem in PL/SQL Report

Following steps will resolved the date issue 

1) While creating Package/Procedure make sure date parameter data type should be varchar2

     create or replace package xx_pkg
       as
               procedure xx_p (
                   errbuf                out varchar2,
                   retcode               out varchar2,
                   p_agreement_start_date     in     varchar2,
                   p_agreement_end_date      in     varchar2);
     end xx_pkg;
     /

   create or replace package body apps.xx_pkg
       as
          procedure xx_p (errbuf                      out varchar2,
                                     retcode                     out varchar2,
                                     p_agreement_start_date   in     varchar2,
                                     p_agreement_end_date     in     varchar2)
   is
      cursor c1 (v_agreement_start_date    varchar2,
                       v_agreement_end_date      varchar2)
      is
         select xx.*
           from xx
          where  xx.start_date_active=nvl(v_agreement_start_date,xx.start_date_active)
           and xx.end_date_active=nvl(v_agreement_end_date,xx.end_date_active)
           and xx.end_date_active between v_agreement_start_date and v_agreement_end_date;

       v_agreement_start_date date;
       v_agreement_end_date date;
   begin
   v_agreement_start_date   := fnd_date.canonical_to_date (p_agreement_start_date);
   v_agreement_end_date   := fnd_date.canonical_to_date (p_agreement_end_date);

    fnd_file.put_line (fnd_file.output, '<OUTLOOP>');
      for i in c1(v_agreement_start_date,v_agreement_end_date)
      loop
        fnd_file.put_line (fnd_file.output, '<INLOOP>');
            fnd_file.put_line ( fnd_file.output,'<customer_name>'i.customer_name'</customer_name>');
        fnd_file.put_line (fnd_file.output, '</INLOOP>');
      end loop;
    fnd_file.put_line (fnd_file.output, '</OUTLOOP>');
   end xx_p;
end xx_pkg;
/

2) While creating Concurrent program parameter make sure parameter Value Set should be FND_STANDARD_DATE