FTP client can create messages with zero bytes

Symptom

Using Sterling Integrator 5.0 and build 5006.   Sterling Integrator is the FTP Server.   Intermittently an FTP Client will send a file with 0 bytes.   A message is created in Sterling Integrator with 0 bytes.   SSL is not being used. 

A network trace showed no data packets were received by Sterling Integrator FTP server.    Data packets were sent by the FTP client but lost before reaching Sterling Integrator FTP server.

FTP Server log with Communication Trace reports:

[2011-02-16 11:08:52.638] COMMTRACE 000000000000 GLOBAL_SCOPE user=[<unknown>], ip=[12.3.45.67], type=[REPLY], msg=[220 GIS FTP Server (java -1.1.00) ready.

[2011-02-16 11:08:52.65] COMMTRACE 000000000000 GLOBAL_SCOPE user=[<unknown>], ip=[12.3.45.67], type=[REQUEST], msg=[user ftpuser]
[2011-02-16 11:08:52.65] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REPLY], msg=[331 Password required for ftpuser.
]
[2011-02-16 11:08:52.663] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REQUEST], msg=[pass password]
[2011-02-16 11:08:52.665] ALL 000000000000 GLOBAL_SCOPE AUDIT: User [ftpuser] from [12.3.45.67] has logged in using unsecure channel.
[2011-02-16 11:08:52.665] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REPLY], msg=[230 User ftpuser logged in.
]
[2011-02-16 11:08:52.678] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REQUEST], msg=[PORT 12,3,45,67,21,211]
[2011-02-16 11:08:52.678] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REPLY], msg=[200 PORT command successful.
]
[2011-02-16 11:08:52.691] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REQUEST], msg=[STOR FTP.Data.File.txt]
[2011-02-16 11:08:52.692] ALL 000000000000 GLOBAL_SCOPE AUDIT: User [ftpuser] storing file [/FTP.Data.File.txt].
[2011-02-16 11:08:52.704] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REPLY], msg=[125 Data connection already open; transfer starting.
]
[2011-02-16 11:08:52.788] TIMER 000000000000 GLOBAL_SCOPE FtpFile.closeWrite() - Storing 0.00 MB/sec. (0.00 MB transferred (0 Bytes). Logging Off) : start=1297872532704 - end=1297872532788
[2011-02-16 11:08:52.788] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REPLY], msg=[226 Closing data connection, ASCII transfer complete.
]
[2011-02-16 11:08:52.893] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REQUEST], msg=[quit]
[2011-02-16 11:08:52.893] ALL 000000000000 GLOBAL_SCOPE AUDIT: User [ftpuser] from [12.3.45.67] has quitted.
[2011-02-16 11:08:52.893] COMMTRACE 000000000000 GLOBAL_SCOPE user=[ftpuser], ip=[12.3.45.67], type=[REPLY], msg=[221 Goodbye.