BAPI_BUS2001_SET_STATUS is not working in bag round mode

Hi Gurus,

I need to use BAPI_BUS2001_SET_STATUS for 'REL' status in baground mode.

but i got one error 'Error in processing. Function was not executed'.

please tell me any other option or guide me to pass correct parameter to above function moduele.

currently i m passing values like ,

CALL FUNCTION 'BAPI_BUS2001_SET_STATUS'

EXPORTING

project_definition = project_definition

set_system_status = 'REL'

IMPORTING

return = it_return.