[Samba] Serious grief with a Samba connection

[Dan White]

The server is on a Sun box (uname says SunOS 5.8)
I do not know what version of samba is running

For the last year and a half, I have made a daily connection from a  
Windows XP box with the following command:

new use G: \\server\volume /USER:userid password

This makes a "G" network drive that serves the purpose.

About a month ago, network folks upstream from us spewed a bunch of  
policy updates that caused serious trouble.  The worst being mine.

Now, if I try the same command on an XP box, the command executes  
successfully, the G-drive appears and then blinks to say  
"Disconnected Network Drive"

Because some of our team use them, I tried from a Windows 2000 box.   
The same command responds with :

System Error 1240 has occurred.  The account is not authorized to log  
in from this station"

I checked the smb.conf file and found that the samba server is  
configured for encrypted passwords.  This error makes no sense.

The local network folks are convinced this is a Unix problem.

Any clues out there for this clueless one ?