Runtime Error in OPEN DATASET

Question

Dear All,
I am trying to upload a text file in application server. But I am getting the run time error which says-
" For the statement
    "TRANSFER f TO ..."
only character-type data objects are supported at the argument position
"f".
In this case. the operand "f" has the non-character-type "u". The
current program is a Unicode program. In the Unicode context, the type
'X' or structures containing not only character-type components are
regarded as non-character-type."
If I remove the quantity fields then the error does not happen. But I have to take quantity fields also. Plz tell me what to do. My code is,
DATA FILENAME like rlgrap-filename VALUE 'MIGO_VALUE.txt'.
TABLES VBAK.
DATA D_MSG_TEXT(50).
DATA : BEGIN OF it_mseg OCCURS 0,
       mblnr TYPE mseg-mblnr,
       mjahr TYPE mseg-mjahr,
       matnr TYPE mseg-matnr,
*       erfmg TYPE mseg-erfmg,
       werks TYPE mseg-werks,
       lgort TYPE mseg-lgort,
       END OF it_mseg.
DATA wa LIKE it_mseg.
SELECT mblnr mjahr matnr werks lgort FROM mseg INTO CORRESPONDING FIELDS OF TABLE it_mseg WHERE bwart = '101'.
SORT it_mseg BY mblnr.
OPEN DATASET FILENAME FOR OUTPUT IN TEXT MODE ENCODING DEFAULT
                      MESSAGE D_MSG_TEXT.
if sy-subrc eq 0.
message 'File created succesfully in SAP System'(002) type 'S'.
endif.
IF SY-SUBRC NE 0.
  WRITE: 'File cannot be opened. Reason:', D_MSG_TEXT.
  EXIT.
ENDIF.
* Transferring Data
LOOP AT it_mseg INTO wa.
TRANSFER wa to filename.
ENDLOOP.
* Closing the File
CLOSE DATASET FILENAME.
Thanks,
Tripod.

Answer 1

Thanks Sri for your help. I tried to apply the logic, but the  error i am getting here is -
"IT_MSEG-ERFMG" must be a character-like data object (data type C, N,D, T, or STRING) STRING).
Same case here, if I remove ERFMG field, i do not get such error.
data ld_string type string.
LOOP AT it_mseg INTO wa.
  CONCATENATE it_mseg-mblnr it_mseg-mjahr it_mseg-matnr it_mseg-erfmg it_mseg-werks it_mseg-lgort INTO ld_string.
     endloop.
With regards,
Tripod.