Thanks reply.
My client computer is WinXP Professional SP3. I just apply the registry patch found, winxplogon.reg.
In the WinXP, the workgroup name and domain are used to be the same, "xxx". I already tried to change the workgroup name to "yyy", reboot WinXP. But the problem persists.
In WinXP, I can use Windows Explorer to browse the shared folder on the SME server. When I did it, I can access it by the user created in SME server. But one thing, the login fail if I access it as user "admin". Is it normal? But I can use puTTy (ssh applicaton) to login SME server as "admin".