[Samba] strange [homes] behavior

[Hamish]

Hello
I am having a very trippy time trying to get the [homes] share to work 
on my samba 3.0.3pre2-SuSE (SuSE 9.0) server working.
Users home folders have been copied from an old sbs server to 
/data1/fileroot/PersonalFiles.
Here is the [homes] section of my smb.conf:

[homes]
    path = /data1/fileroot/PersonalFiles/%S
    valid users = %S
    admin users = MYDOMAIN\administrator
    browseable = No
    exec = echo u=%u S=%S >> /data1/fileroot/ITManagement/connhome.rtf

The exec= is my attempt at making sure the variables are subsituted 
properly (this still does not work all the time, even though the file is 
chmod 777).

The correct directory always shows in explorer when the server is 
connected to ie \\samba\fred but only works SOMETIMES - i cannot figure 
out what causes this! Sometimes the comment for the directory (in 
windows explorer) is "Home directory of DOMAIN\User", sometimes it is 
"Home directory of User" - Same user, same box, after disconnecting the 
user or the user rebooting his xp machine, it will change and prompt for 
authentication, sometimes it will just let him in. During this the samba 
server has not been touched, connected to or looked at.

I do not know if it is related, but i occasionally get the following in 
log.smbd:
[DateTime, 0] lib/substitute.c:alloc_sub_basic(505)
  alloc_sub_basic: NULL source string!  This should not happen

If I remove valid users=%S, the users can all connect succesfully to 
their home directories - the problem with this is that they can also 
connect to anyone elses home directory.

The only other alternative I can think of is to individually set 
permissions on each users home folder, which will take quite a while!  
Any suggestions?

Thanks,
Hamish