Abt update

Hello,

          While doing a maintenance subfile  , i got a problem.. the edit i
do in the screen is not reflected in the data base,
 i used update for changing database , i am pating section of code below ..
please point out error.



0320.00 C                   WRITE     FOOTER
0321.00 C                   EXFMT     CUSTMTCTL
0322.00 C**  IF F5 IS PRESSED PROCESS POSSITION VALUE
0323.00 C                   IF        *IN05=*ON
0324.00 C                   DOW       %EOF(CUSTDISP)
0325.00 C                   READC     CUSTMT
0326.00 C                   UPDATE    CUSTREC
0327.00 C                   IF        FLAG='U'
0328.00  **  CALL ROUTINE TO UPDATE SKU DETAIL
0329.00 C*                  EXSR      MTUPDATE
0330.00 C                   ELSEIF    FLAG='D'
0331.00  **  CALL ROUTINE TO DELETE A RECORD
0332.00 C*                  EXSR      MTDELETE
0333.00 C                   ENDIF
0334.00 C                   ENDDO
0335.00 C*                  IF        MTPOSVAL = ' '


update is in line no  0326.00