FM 'END_TIME_DETERMINE' not working

Hello Experts,

I am developing a report in CRM, where I am using function module 'END_TIME_DETERMINE' to add or subtracts days.

call function 'END_TIME_DETERMINE'
  exporting
        duration                        = 2
         unit                             = 'D'
         factory_calendar                 = 'IN'
  importing
         end_date                         = final_Date
         end_time                         = final_time
  changing
         start_date                       = sy-datum
         start_time                       = sy-uzeit
  exceptions
         factory_calendar_not_found       = 1
         date_out_of_calendar_range       = 2
         date_not_valid                   = 3
         unit_conversion_error            = 4
         si_unit_missing                  = 5
         parameters_no_valid              = 6
    others                           = 7
           .

When I pass duration = 0, I am getting sy-sybrc = 0.

but when I pass duration = 2 or any other value, then returning sy-subrc = 4.

When I execute the same case i.e. duration other than 0, in SE37, it is working perfectly.

Please help.

Regards,

Nikhil