[Mediawiki-l] Upload Error always

[Gack, Dietmar]

hello, 
I've started with installing a media wiki server on a linux computer. 
I did it twice one at home (arch linux 0.7) and one at my job (mandrake 10.0). I used for both the same installation: XAMPP Linux 1.4.11 (Apache 2.0.52, MySQL 4.1.8, PHP 5.0.3 ...) and MediaWiki 1.3.9. 

On the "mandrake" one I can't upload, neither locally nor from a remote Windows computer. But on the "arch" one it works, at least locally. 
I have the setting in php.ini: "file_uploads = On" and "upload_max_filesize = 2M". The "images" directory is given free. 

I get always this error: 
---
Upload error 
# The file you uploaded seems to be empty. This might be due to a typo > in the file name. Please check whether you really want to upload this > file. 
---

I get this error independent how big the file is, 100k or lower. Even I figured out that I get the same error if the access to folder "images" isn't allowed or if it isn't at all here. 

I don't know where to search anymore, can you give me any pointer? Are there more settings and dependencies I missed?

Thanks a lot 
Dietmar