PUBLIC MARKS with tags network & xp

I restored my host computer and now I cannot get to folders in "My Network Places" although I can see them from both computers. The error message is Downstairs is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. The network path was not found." This error message is on both computers. The host computer is a Windows XP Home operating system and the second computer is a Windows XP Professional operating system. The 2nd computer is named downstairs and the 1st (host) computer is named upstairs. I get the same error message on both computers; that is, the downstairs computer says "Upstairs is not accessible...... I am the administrator and I rebooted both computers and log in as the administrator. Any suggestions?