Odd problem with ftp/filezilla

[Janos Dohanics]

Hello All,

I can upload some files, but not others.

Server: 12.1-STABLE r361323 and pure-ftpd-1.0.49_1
Client: 12.1-STABLE r361661 and filezilla-3.40.0_5

14:24:15	Status:	Initializing TLS...
14:24:15	Status:	Initializing TLS...
14:24:15	Status:	Verifying certificate...
14:24:15	Status:	TLS connection established.
14:24:15	Status:	Verifying certificate...
14:24:15	Status:	TLS connection established.
14:24:18	Status:	Logged in
14:24:18	Status:	Starting upload of KiwiBox.gif
14:24:18	Status:	Logged in
14:24:18	Status:	Starting upload of 980111-008.jpg
14:24:19	Command:	CWD /htdocs
14:24:19	Response:	250 OK. Current directory is /htdocs
14:24:19	Command:	TYPE I
14:24:19	Response:	200 TYPE is now 8-bit binary
14:24:19	Command:	PASV
14:24:19	Response:	227 Entering Passive Mode (x,x,x,x,167,166)
14:24:19	Command:	STOR 980111-008.jpg
14:24:19	Response:	150 Accepted data connection
14:24:19	Response:	451-Error during read from data connection
14:24:19	Response:	451 Transfer aborted
14:24:19	Error:	File transfer failed
14:24:19	Status:	Starting upload of 980111-008.jpg
14:24:19	Status:	Retrieving directory listing of "/htdocs"...
14:24:20	Status:	File transfer successful, transferred 5148 bytes in 1 second
14:24:20	Status:	Starting upload of apctest.output
14:24:25	Status:	Skipping upload of 980111-008.jpg
14:24:25	Status:	File transfer successful, transferred 443 bytes in 5 seconds
14:24:25	Status:	Starting upload of camping_pictures.htm
14:24:26	Status:	File transfer successful, transferred 4323 bytes in 1 second
14:24:26	Status:	Starting upload of zzz_Job_log.ods
14:24:28	Command:	TYPE I
14:24:28	Response:	200 TYPE is now 8-bit binary
14:24:28	Command:	PASV
14:24:28	Response:	227 Entering Passive Mode (x.x.x.x,157,110)
14:24:28	Command:	STOR zzz_Job_log.ods
14:24:28	Response:	150 Accepted data connection
14:24:28	Response:	451-Error during read from data connection
14:24:28	Response:	451 Transfer aborted
14:24:28	Error:	File transfer failed
14:24:28	Status:	Starting upload of zzz_Job_log.ods
14:24:28	Status:	Retrieving directory listing of "/htdocs"...
14:24:29	Status:	Skipping upload of zzz_Job_log.ods
14:24:29	Status:	File transfer successful, transferred 806 bytes in 1 second
14:25:25	Status:	File transfer successful, transferred 6274877 bytes in 65 seconds
14:25:25	Status:	Retrieving directory listing of "/htdocs"...
14:25:26	Status:	Directory listing of "/htdocs" successful
14:25:29	Status:	Disconnected from server

Successful:

-rw-r--r--  1 ftpusers  ftpgroup     5148 Feb 20  2011 KiwiBox.gif
-rw-r--r--  1 ftpusers  ftpgroup  6274877 Apr 16 15:37 apctest.output
-rw-r--r--  1 ftpusers  ftpgroup     4246 Feb 20  2011 camping_pictures.htm

Unsuccessful:

-rw-r--r--  1 ftpusers  ftpgroup        0 Jun  7 14:24 980111-008.jpg
-rw-r--r--  1 ftpusers  ftpgroup        0 Jun  7 14:24 zzz_Job_log.ods

The same 12.1-STABLE computer also is a host to a Virtualbox/Win7
instance with filezilla-3.40.0 installed, and no uploading problems
from there.

Could you please give me a hint?

-- 
Janos Dohanics