samba - Sep 2006 - Windows xp cannot acces some shares but smbclient can

Samba 3.0.22 .. 3.0.23b configured with security=domain, joined to windows 2003.

Samba has two shares, lets name them joe and joe1, with exactly the same 
definition (copy/pasted, just the name differs)

Share definition like this
[joe]
  path = /opt/joe
  writeable = yes
  force user = joe
  force group = users
  valid users = domain/user1, domain/user2 etc.

 From smbclient both shares work (of course, they have the same definition)

 From windows xp client (logged in as domain/user1 or domain/user2) joe is not 
accessible (no error from windows but doesn't enter it) but joe1 works.
Oops.

As long as the share has any other name than joe, it works.

Same problem for a second share (windows cannot access it if share name equals 
local force user name), but not for a third share tested with another local 
user. Now I'm really confused.

Debug is pretty long and does not (at least to me) reveal any obvious error, 
but I can attach it on request. Any ideas?

-- 
Dan Borlovan
Level 7 Software