[Samba] missing domain

[ashley maher]

I have a samba 3 install with 14 new xp pro clients.

13 of these I was able to join to the domain without any problems. (ie
create machine accounts)

The 14th required a warranty repair and I went to put it onto the domain
recently (several weeks intervening).

This machine claims there is no such domain when I try to join the
domain.

If I use on the rouge machine:

\\servername\sharename

I am prompted for a username-pwd combination and shows the share with no
problems.

If I use tcpdump during the above test it gives good output.

However if I use tcpdump during a join the domian attempt no traffic is
generated (on port 139 or 445)

Clearly I'm missing something silly somewhere that is "obviouse" and I
can't see so any ideas greatfully received.

The 13 other XP Pro machines are happy.

Regards,

Ashley
PS I even disabled the XP sign or seal just in case, which I've not
needed to do for a while.