XP Pro can’t access W2K server share

I have a Windows NT 4 network with a few W2K member servers on it. I just put our first XP Pro client on the network and when I try to access shared folders on any of the W2K servers, I get the following error message: \\”W2K Server Name” is not accessible. You may not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions.
I am a domain admin and this is my computer so I know I have permission. Also, I can’t map tothe administrative share on any of the W2K servers but can on the WinNT servers. I even specifically shared a folder on one of the W2K servers and gave myself full access to the folder but I still can’t connect to it. I don’t understand why.