samba - Jan 2004 - The specified Network Name is no longer available

I have installed samba 3.0.1 on a Solaris 8 server. I can configure new
shares using SWAT but when I try to connect to the share over our Windows
2000 network I get the following error:

"The specified Network Name is no longer available"

I have 5 or 6 other Solaris servers running samba 2.2.2 without any
problems and I have tried using some of these smb.conf but that makes no
difference.

I'm guessing it is only something small that I have overlooked but any help
would be much appreciated.

Thanks

Sean