The Smart Form that is CREATED in the Development may not have the same name in the Production server. So it is always advised to use the Function Module 'SSF_FUNCTION_MODULE_NAME' to get the Function Module name by passing the Smartform name. 

DATA: fm_name TYPE rs38l_fnam. 
CALL FUNCTION 'SSF_FUNCTION_MODULE_NAME' 
EXPORTING 
FORMNAME = 'ZSMARTFORM' 
IMPORTING
fm_name = fm_name 
EXCEPTIONS 
no_form = 1 
no_function_module = 2 
others = 3. 
IF sy-subrc <> 0. 
MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno 
WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4. 
ENDIF. 
CALL FUNCTION fm_name 
EXCEPTIONS 
formatting_error = 1 
internal_error = 2 
send_error = 3 
user_canceled = 4 
others = 5. 
IF sy-subrc <> 0. 
MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno 
WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4. 
ENDIF.

Once you transport the Smartform from Development to Production server, a NEW function module name for the Smartform in generated in the Production server. For a particular Smartform , generated function module names are different in different systems. 

The Smart Form that is created in the Development may not have the same name in the Production server. So it is always advised to use the Function Module 'SSF_FUNCTION_MODULE_NAME' to get the Function Module name by passing the Smartform name. 

DATA: fm_name TYPE rs38l_fnam. 
CALL FUNCTION 'SSF_FUNCTION_MODULE_NAME' 
EXPORTING 
formname = 'ZSMARTFORM' 
IMPORTING
fm_name = fm_name 
EXCEPTIONS 
no_form = 1 
no_function_module = 2 
others = 3. 
IF sy-subrc <> 0. 
MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno 
WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4. 
ENDIF. 
CALL FUNCTION fm_name 
EXCEPTIONS 
formatting_error = 1 
internal_error = 2 
send_error = 3 
user_canceled = 4 
others = 5. 
IF sy-subrc <> 0. 
MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno 
WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4. 
ENDIF.

Once you transport the Smartform from Development to Production server, a new function module name for the Smartform in generated in the Production server. For a particular Smartform , generated function module names are different in different systems.