Hi,
You need to modify your code. Let's assume that lv_fname is a string (or char) variable that contains the name of the result fields.
Then, this is what you do.
* Put the below line along with your declarations
FIELD-SYMBOLS: <tgt_fld> TYPE ANY.
* Use the below two lines to populate the result field
ASSIGN COMPONENT lv_fname OF STRUCTURE <result_fields> TO <tgt_fld>.
<tgt_fld> = 'Some_value'.
Regards,
Suhas