Hi Padmaja,
Did you put a breakpoint on 'CASE i_datasource.' statement? Can you see if you have received data in table c_t_data? This is ideally the table which is populated by standard code and rest is filled up by BADI code.
Do you recieve data in your datasource? or are the records 0 in RSA3? I mean to say that do you have data in your table MAKT?
Coming to next doubt - 'DATA: l_t_mattext TYPE TABLE OF biw_makt_s.' I agree that biw_makt_s is structure but when in our code we define l_t_mattext as a type table of biw_makt_s, then l_t_mattext actually takes the structure of biw_makt_s and gets declared as internal table. So this is ideally a internal table of structure biw_makt_s (i.e. having all fields of this structure).
If when you debug the code and you do not receive any data in c_t_data, then I would think that you do not have relevant data for this datasource in your table MAKT.
Let me know if yoits otherwise.
Thanks
Amit