Cannot access shared drive on W2k3 server

When attempting to access the shared drives on a W2k3 server from a windows Xp machine, we get a box :
\\server is not accessible. You might not have permission to use this network resource. Contact the administrator.
Multiple connections to a server or shared resource by the same user, using more than one user name, are not allowed.
This is happening on two machines, but is not happening on others with the same username and password. I've allready checked and it does not appear to be a licensing issue.
Any help would be greatly appreciated.

 

As a rule of thumb with problems connecting to Windows AD systems, the first thing to check is the DNS settings on the XP PCs. The W2k3 server's IP address needs to be set as the XP PC primary DNS server. If this is not set correctly you get name resolution problems that often manifest as connection problems.