Help me please, with haproxy.cfg for FTP Server.

Dear. w#1wt.eu, haproxy#formilux.org               

    How i can config haproxy for load balance my ftp server. now my haproxy.cnf

listen MyFTP 10.129.37.18:21

        mode tcp
        option tcplog
        balance roundrobin
        server my-ftp1 10.129.37.107:21 weight 10 minconn 30 maxconn 1000 check
        server my-ftp2 10.129.37.108:21 weight 10 minconn 30 maxconn 1000 check
        server my-ftp3 10.129.37.109:21 weight 10 minconn 30 maxconn 1000 check

Now i can ftp to 10.129.37.18. but cannot list my folder.

C:\>ftp 10.129.37.18
Connected to 10.129.37.18.
220 ::ffff:10.129.37.107 FTP server ready User (10.129.37.18:(none)): jirapong_kij 331 Password required for jirapong_kij
Password:
230 User jirapong_kij logged in
ftp> ls
500 Illegal PORT command
Aborting any active data connections...
ftp> bye
Aborting any active data connections...

C:\>
C:\>ftp 10.129.37.107
Connected to 10.129.37.107.
220 ::ffff:10.129.37.107 FTP server ready User (10.129.37.107:(none)): jirapong_kij 331 Password required for jirapong_kij
Password:
230 User jirapong_kij logged in
ftp> ls
200 PORT command successful
150 Opening ASCII mode data connection for file list public_html
226 Transfer complete
ftp: 13 bytes received in 0.00Seconds 13.00Kbytes/sec. ftp>                                              

                                                                                                             Thank You