Files disappear after copying them with Finder to a Linux Samba share

Hi,

I've spent some time looking for posts concerning my problem but the only one which seems to be specific is this old thread from 2003:
http://lists.samba.org/archive/samba-technical/2003-November/033053.html

I run a Samba server (v3.0.26a) under Ubuntu Linux and share an ext3-harddisk via smb.
Under Windows XP I can write files to this share without problems, under the Finder of OS X (I only tried 10.5.2) I encounter the following issue:
When I copy a file that hasn't been created on a Mac (e.g. a jpg or a pdf) to this share using Finder, it seems to work ok but a split second after the copy process is finished the file gets deleted again. The file just disappears without an error message.
If I copy the same file for up to 3 times it will eventually stay. Deleting a file on the share leads to analogous problems.
I found two workarounds:
If I create a folder e.g. on my OS X desktop and copy all the files I want to copy to the Samba share first to this folder and then drag the whole folder to the share, all files arrive without problems.
If I use a different application than the Finder to copy files it also works without a problem, e.g. KopyMac ( http://www.tcsn.net/mont/DigitolDisturbance/DigitolDisturbance.html) or muCommander ( http://www.mucommander.com/).
I tried to disable .DS_Store files on network drives as described in this article:
http://docs.info.apple.com/article.html?artnum=301711
but it also didn't help.

So, to sum up, if I copy files with the Finder to a Samba share these files disappear again directly after copying.

Does anyone know a solution to this issue?

Thanks in advance

Till