Connection suddenly hangs-up after 1 week of operation

Hello guys,

I am using winscp 4.0.0 (Build 342) to do the uploading and downloading tasks from our sftp server(SFTP-3). All goes well, until 1 week of straight operation. The server suddenly stops responding. I don't think it concerns about network connection since the application(java) who calls sftp operation can run fine if it is restarted after the hang-up is discovered. Below is the snippet of the logfile:

. 2010-02-08 10:02:47.750 --------------------------------------------------------------------------
. 2010-02-08 10:02:47.750 WinSCP Version 4.0.0 (Build 342) (OS 5.2.3790 Service Pack 2)
. 2010-02-08 10:02:47.750 Login time: Monday, February 08, 2010 10:02:47 AM
. 2010-02-08 10:02:47.750 --------------------------------------------------------------------------
. 2010-02-08 10:02:47.750 Session name: username@xxx.xxx.xx.xx
. 2010-02-08 10:02:47.750 Host name: xxx.xxx.xx.xx (Port: 22)
. 2010-02-08 10:02:47.750 User name: usrname (Password: Yes, Key file: No)
. 2010-02-08 10:02:47.750 Tunnel: No
. 2010-02-08 10:02:47.750 Transfer Protocol: SFTP (SCP)
...
...
> 2010-02-08 10:02:48.437 Type: SSH_FXP_REALPATH, Size: 10, Number: 16
< 2010-02-08 10:02:48.468 Type: SSH_FXP_NAME, Size: 53, Number: 16
. 2010-02-08 10:02:48.468 Real path is '/cygdrive/c/FTPFolder'
. 2010-02-08 10:02:48.468 Startup conversation with host finished.
. 2010-02-08 10:02:48.468 Copying 1 files/directories to remote directory "/cygdrive/c/FTPFolder"
. 2010-02-08 10:02:48.468 PrTime: Yes; PrRO: Yes; Rght: rw-r--r--; PrR: No (No); FnCs: N; RIC: 01; Resume: S (102400); CalcS: No; Mask: .\\FOLDER2\\data\\data_02082010_100247171_1.xml
. 2010-02-08 10:02:48.468 TM: B; ClAr: No; ExclM(No):
. 2010-02-08 10:02:48.468 AscM: *.*html; *.htm; *.txt; *.php*; *.cgi; *.c; *.cpp; *.h; *.pas; *.bas; *.tex; *.pl; .htaccess; *.xtml; *.css; *.cfg; *.ini; *.sh; *.xml
. 2010-02-08 10:02:48.468 File: ".\\FOLDER2\\data\\data_02082010_100247171_1.xml"
. 2010-02-08 10:02:48.468 Copying ".\\FOLDER2\\data\\data_02082010_100247171_1.xml" to remote directory started.
. 2010-02-08 10:02:48.468 Binary transfer mode selected.
. 2010-02-08 10:02:48.468 Opening remote file.
> 2010-02-08 10:02:48.468 Type: SSH_FXP_OPEN, Size: 95, Number: 259
< 2010-02-08 10:02:48.500 Type: SSH_FXP_HANDLE, Size: 13, Number: 259
> 2010-02-08 10:02:48.500 Type: SSH_FXP_WRITE, Size: 3270, Number: 774
> 2010-02-08 10:02:48.500 Type: SSH_FXP_CLOSE, Size: 13, Number: 1028
> 2010-02-08 10:02:48.500 Type: SSH_FXP_SETSTAT, Size: 91, Number: 521
< 2010-02-08 10:02:48.531 Type: SSH_FXP_STATUS, Size: 24, Number: 774
< 2010-02-08 10:02:48.531 Status/error code: 0
. 2010-02-08 10:24:51.968 --------------------------------------------------------------------------
. 2010-02-08 10:24:51.968 WinSCP Version 4.0.0 (Build 342) (OS 5.2.3790 Service Pack 2)
. 2010-02-08 10:24:51.968 Login time: Monday, February 08, 2010 10:24:51 AM
. 2010-02-08 10:24:51.968 --------------------------------------------------------------------------
...
...

As you can see, the above session is not closed, which causes the process(java) to hang-up.

I would appreciate if somebody direct me to the right path.

Thanks,
Rey

Sorry, I do not understand what the log file should show. Please try to explain again.