[Samba] group setting doesnt work (debian)

[Rene Veerman]

I'm trying to connect from a vista machine to a samba share on debian 
(latest).

This is going fine with these settings:
[global]

 directory security mask 0775
 security mask 0775
 create mask 0775
 directory mask 0775

   workgroup = nlstr

   server string = %h server

   panic action = /usr/share/samba/panic-action %d
   encrypt passwords = true

   passdb backend = tdbsam

   obey pam restrictions = yes

   invalid users = root

   passwd program = /usr/bin/passwd %u
   passwd chat = *Enter\snew\sUNIX\spassword:* %n\n 
*Retype\snew\sUNIX\spassword:* %n\n *password\supdated\ssuccessfully* .

   socket options = TCP_NODELAY

   writable = no

   users = %S

[web]
path = /data/web
writeable = yes


-------------------EOF

but as soon as i add the following line to [web], i cannot connect 
anymore; i get an error message on vista that reads 'the specified group 
does not exist.'

group = www-data

the thing is, this group DOES exist, it's in /etc/group and the username 
i'm connecting with is a member of that group.

There's an additional problem, my files are created with these permissions;
-rwxr--r--  1 rene rene     0 2008-11-10 17:16 test.txt*

but that should be
drwxrwxr-x  5 rene rene  4096 2008-11-03 14:48 work/

i'm kinda at a loss here, holding out for clues..