username problem

[Jo De Troy]

Hello,

I'm trying to set up samba 2.0.7 on a  Solaris  machine
Most of the useraccounts have the form "firstname.lastname"
When I try to access a samba share with smbclient I get the error:
session setup failed: ERRSRV - ERRbadpw (Bad password - name/password
pair in a Tree Connect or Session Setup are invalid.)

For normal usernames (no dots in them) I have no problem in connecting.
Any ideas?

TIA,
Jo