Is user password cached on nt? Errors 87 or 2219

[shapi003 at mc.duke.edu]

I used smbpasswd -U puffin and assigned a password

This was a user I used previously on nt for other samba logins.  I try to net
use to the server but it keeps whining about incorrect password (error 87 I
think).  If I make a new user on unix box and then net use to it and connect
successfully, and then I try to use the previous login that was giving me a
problem, I get a message about credentials supplied conflict with an existing
set of credentials (error 2219).  What gives?