Connecting to a Samba server from a Windows PC

I have a Linux machine which is on my network but not on my domain. I have a Windows XP pro PC which is on the domain that I am trying to connect to a share on the Linux box.

When, from a DOS prompt, I type

net use r: \\\sharename

I get “The password or username is invalid for \\\sharename”

Enter user name for ‘linuxserver’ :

I supply my credentials but regardless of which login I use I always get Logon Failure. I have tried to supply root credentials, I have created an account on the Linux machine with the same user name and password as my domain account but so far no luck. Can I connect from a domain PC to a non-domain Linux box? Is there something else I should be checking?