Emacs failed in reading file from ftp

[Unknown <unknown@unknown.invalid>]

Hello,

I got a (big) problem:

My emacs (GNU Emacs 21.4.1 (i486-pc-linux-gnu, X toolkit, Xaw3d scroll 
bars) of 2007-06-19 on ninsei, modified by Debian), running on debian 
etch has a problem while reading files from an ftp server (pureFTP). 
This is an error that occurs not everytime, but today I have a file of 
7,5 MByte, but the emacs Editor reads only a "few" bytes, sometimes 
128K sometime 260K without any schematic. This error occurs sometimes 
without warning: I read an php-file from the the server, store it, run 
it, and an error occurs: the file is broken, not all was loaded (a part 
of the end was missing), I haven't noticed it, change something, store 
and: I loose my file (but I can recovered from the incrementell backups).

The in the *Messages* buffer shows the error:
[...]
call-interactively: End of buffer [6 times]
Retrieving www-data...260k
Retrieving www-data...done
call-interactively: Quit [2 times]
exchange-point-and-mark: No mark set in this buffer [2 times]
[...]

Where www-data is the file of 7,5 MByte data.

The ftp-server shows following in the logs:
Jan 16 18:09:35 localhost pure-ftpd: (wwwtest@127.0.0.1) [NOTICE] 
//home/wwwtest/public_html/class_readmail/www-data downloaded  (7568015 
bytes, 285175.62KB/sec)
Jan 16 18:09:44 localhost pure-ftpd: (wwwtest@127.0.0.1) [NOTICE] 
//home/wwwtest/public_html/class_readmail/www-data downloaded  (7568015 
bytes, 249759.01KB/sec)

and so on. More than 20 downloads, all occurs into the log with the 
same filesize and without any warning... So I think: It's emacs...

Sometime: I couldn't read any file from ftp-server. After 3-6 retries, 
it works...

Who knows this problem, what is the reason and where should I search?

Thanks in advance
Frank B.

-- 
"Unterwerfung ist die einzige bequeme Antwort auf Autorität"