spool not created

Hi Friends

spool is not getting created for the below code:

p_sf_name = 'ZPO'.

CALL FUNCTION 'SSF_FUNCTION_MODULE_NAME'

EXPORTING

formname = p_sf_name

IMPORTING

fm_name = fm_name

EXCEPTIONS

no_form = 1

no_function_module = 2

OTHERS = 3.

wa_outop-tdimmed = 'X'.

wa_control_parameters-no_dialog = 'X'.

wa_control_parameters-device = 'PRINTER'.

wa_control_parameters-preview = ''.

wa_control_parameters-langu = 'EN'.

wa_outop-tdarmod = 1.

wa_outop-tdimmed = 'X'.

CALL FUNCTION fm_name

EXPORTING

output_options = wa_outop

user_settings = space

wa_label_data = wa_label

control_parameters = wa_control_parameters

EXCEPTIONS

formatting_error = 1

internal_error = 2

send_error = 3

user_canceled = 4

OTHERS = 5.

Please help.

Thanks

Ramesh