Alex,

I'm not a Samba wiz but I do use it quite a bit in the Security=Domain mode, so I'm not up on Security=Share.

I took a quick look at the Samba FAQ here and it looks like it is creating a public share, thus your ability to write to /tmp.

Using Security=Share I believe you must try to access the share using the username/password that has has write access to the directory (knoppix user name with the knoppix user passowrd on the knoppix box).

So try this: Create an account on your XP box with the same user name and password (knoppix) as you would use to write to the /home/knoppix directory, or map the drive using the knoppix user and password.

I believe samba is going to look at the /etc/passwd file to make sure the user trying to use the share has the appropriate rights and is a valid user.

Check this to: http://us3.samba.org/samba/docs/man/....html#SECURITY
and look at the section on Security=Share. You might want to try changing the security to Security=User.

Rememebr to restart samba after changes to smb.conf (/etc/init.d/samba restart)

Hopefully someone with more Samba knowledge can give you better instructions.

Mike