channel_request: Channel request subsystem failed

[saeed <ssmixpro@xxxxxxxxx>]

Hi,
I'm trying to open an sftp session to my gateway , but i get the error :
"channel_request:  Channel request subsystem failed",
I have no idea what is the problem is since using a winscp client works .
attached is the full log of the error .
Please i need help because its an important issue and , i can't do anything
without solving it .

-----------
Have a good day
Saeed Hardan

[2014/10/15 10:10:47.698264, 1] ssh_connect:  libssh 0.6.1 (c) 2003-2014 Aris Adamantiadis, Andreas Schneider, and libssh contributors. Distributed under the LGPL, please refer to COPYING file for information about your rights, using threading threads_noop
[2014/10/15 10:10:47.700265, 2] ssh_socket_connect:  Nonblocking connection socket: 232
[2014/10/15 10:10:47.700265, 2] ssh_connect:  Socket connecting, now waiting for the callbacks to work
[2014/10/15 10:10:47.700265, 1] socket_callback_connected:  Socket connection callback: 1 (0)
[2014/10/15 10:10:47.705265, 1] ssh_client_connection_callback:  SSH server banner: SSH-2.0-OpenSSH_4.3
[2014/10/15 10:10:47.705265, 1] ssh_analyze_banner:  Analyzing banner: SSH-2.0-OpenSSH_4.3
[2014/10/15 10:10:47.705265, 1] ssh_analyze_banner:  We are talking to an OpenSSH client version: 4.3 (40300)
[2014/10/15 10:10:47.852273, 2] ssh_packet_dh_reply:  Received SSH_KEXDH_REPLY
[2014/10/15 10:10:47.853273, 2] ssh_client_dh_reply:  SSH_MSG_NEWKEYS sent
[2014/10/15 10:10:47.853273, 2] ssh_packet_newkeys:  Received SSH_MSG_NEWKEYS
[2014/10/15 10:10:47.854273, 2] ssh_packet_newkeys:  Signature verified and valid
[2014/10/15 10:10:47.863274, 2] channel_open:  Creating a channel 43 with 64000 window and 32768 max packet
[2014/10/15 10:10:47.864274, 2] ssh_packet_channel_open_conf:  Received a CHANNEL_OPEN_CONFIRMATION for channel 43:0
[2014/10/15 10:10:47.864274, 2] ssh_packet_channel_open_conf:  Remote window : 0, maxpacket : 32768
[2014/10/15 10:10:47.864274, 1] channel_request:  Channel request subsystem failed
Error allocating SFTP session: Channel request subsystem failed