Problem logon to Network/Domain with Windows XP SP2 ver.1

If You Used Static IP Address(Workstation) to Logon to Domain(server) you must set Enable NetBIOS at TCP/IP Properties|Advanced|Wins|Net BIOS Seting|Enable NetBIOS Over TCP/IP. Otherwise set as Default if you used a Dinamic IP(Workstation) DHCP Server(server). See figure below.