[Samba] Windows 2003 server unable to join a Samba PDC

[Christian]

Hello,
I have been trying for hours to make a Windows 2003 Server R2 SP1 join a
Samba PDC.
It does not work, and I simply get an error "Invalid Parameter" on the
2003 side.
I have seen a old post with a similar error on the mailing-list, but w/o
any answers.
I am not using any LDAP stuff, just the flat file smbpasswd & Cie.
I tried on Samba 3.0.20b and also 3.0.23b. It does not make any difference.
If anyone has a clue I'd be most grateful, because I simply don't know
what's going on.

Note : XP, 2000 Pro and 2000 server machines can join the samba domain w/o
trouble.

Thanks