Hi,
Remove REF TO from <FS_RECORD> TYPE REF TO TSTCT.
After Removing look like
<FS_RECORD> TYPE TSTCT.
Or it also work without below statement :
DATA lr_record TYPE REF TO data.
CREATE DATA lr_record TYPE (lr_name).
ASSIGN lr_record->* to <fs_record>.
it will solve your error.
Regards,
Hitesh