I'll keep mtools in mind, but the error I got via WebMin was a result of copying a user file and changing the owner and group into root... but the file did get copied ... :-)
thanks for the help
I got a FAT partition mounted as /mnt, as I believed you only can mount partitions when they are formated, but when I want to copy a file to the /mnt partition I only get errors...should I format it...